My heart goes out to you in your quest, and so I hope to help shed some light on the situation to help you better decide how to proceed with your life's ambitions. I won't begin to try to tell you what you should do or how to live your life, but I hope some information can help to guide you. There are surely many, many people in the same place all over the world, so I hope this will be useful to others as well.
First, it's good to understand the reality of University admission in the USA (and I wouldn't doubt in Europe as well, but I'll leave that to our friends in European countries to confirm/deny). Lots of institutions are proud of their selectivity and the small percentage of applicants they accept (with 2-4% being a commonly cited elite number, in both undergraduate and graduate programs). The numbers cited aren't exactly a lie - but they don't actually mean what people think they mean! These numbers are often intentionally twisted for marketing purposes, so let's get their real meaning.
I'll give you one "worked example". Using publicly available data for one state "flagship" University that reported that only 4% of applicants are accepted, I was able to dig through a number of tables (surprisingly hard to find, took shifting through hundreds of pages of admission statistics), I was able to determine that two sets of statistics were kept and reported: domestic (citizens of the United States) and international (everyone else in the world).
Of the US citizens that applied to the institution and to even one specific department (I picked Engineering as one example, being indeed an international topic), ~40% were admitted. Of the international candidates that were admitted, ~3-4% were indeed admitted. How is that possible? The international applications dwarfed the domestic applications, with more than a 10:1 or even 100:1 ratio in some years! Many US institutions are flooded with international applications, while at the same time engaging in active funded outreach programs to try to find more US citizens to apply to their programs!
Many institutions don't make these stats available, or at least hide them in mountains of other reports no one likely reads, so it's hard to say just how generalized this situation is - but I've yet to view program for a department or speak with someone who has commented that they just don't have enough international applicants for their program. On the other hand I've been contacted by a number of US Universities who actively are trying to head-hunt for applicants from undergraduate and high school programs, etc.
The reality is that at many (all?) institutions in the US, there are two application tracks: one for US citizens, and one for non-citizens. The University/department/program determines an amount of seats available in the program (considering funding, professor availability, etc), and often a set amount of seats are potentially available to international candidates. This can be a flexible number or fixed, but generally it is understood that it is neither desirable nor even possible to accept more than a certain percentage of international students.
This reality is determined by funding sources (many grants and fellowships from the US government are not available to non-citizens), the higher natural rate of failure of international applicants (due to stress of living in a new country, lack of local support resources, preparation/quality of home institutions/education in that country, reliability of foreign test results, and many other factors), bureaucracy (Visas, endorsements, etc), language/culture barriers, local cultures in the US that aren't supportive/accepting of foreign students, etc.
Coming to the USA to study is a hard, hard road, and one that is desired by more people than the road itself is really able to support!
So given the above, what does it take to be admitted to the US?
For one, your application is not in a stack sorted according to % ranking of your country, nor will your application be immediately compared to US candidates (at this stage it doesn't matter how you compare to US candidates in any way - you aren't in that stack yet). Your application goes directly into the other stack - a minority of available seats will be allocated to what is by far the largest stack of applications, simply marked "International".
Being in the top 5% for your country is great, but it isn't something really considered - you will be compared to applicants from every applicable country on earth (other than the US, of course). When you are in a stack this big, honestly even being in the top 10% is great - because you're all probably completely qualified and hard to differentiate. In a world of unlimited resources you'd all be admitted! Honestly, it has nothing to do with what you deserve or have earned at this point - all of this cream of the crop of applicants would be great candidates for admittance to most institutions in the US.
So, how do you stand a chance? Well, for one thing the US is a big place, and every institution sets it's own relative weighting of factors! Some will only accept candidates who've already been to the US before, some will prefer candidates with family here, some will give more weight to reference letters, others will independently evaluate every publication you list in your CV (and will care about little else), others will give greater weight to your personal statement, and yet others will look straight to your grades...etc.
This is where the wisdom of "apply to many places" comes in - because institutions generally do not advertise their weighting criteria! It may even change every year!
What can an "international" applicant to the US do about all this?
Realize that rejection is going to be common - insanely so. The vast majority of applications will not be accepted, and honestly nothing you do will change that reality - rejection is the rule, not the exception, for international applications. And I don't mean 2:1 - even 50:1 shouldn't be a complete surprise.
Apply to many places - you might request fee waivers to help cut the cost down, as some places to understand that $50-200 in US funds is minor here yet an outrageous fee in many countries.
Try to customize your application per institution - this is generally more helpful if you actually know what they are looking for and more about the place so that your application doesn't look like a mass form-letter. You might be applying to lots of places, but - just like when looking for a job - you don't want people reading your application to get that impression! Tailor your statement/application at least a little, if nothing else. If you can even talk with someone in the department who is able to offer some insight into what they are looking for from international applicants, take advantage of that!
Don't be an international applicant. Many people have gone through the expensive, multi-year process of becoming a citizen of a new country and working any menial crappy job they could get just to get the benefits of being a citizen - even though it doesn't guarantee anything. On the other hand, many people just say "screw it".
Be an applicant to a place that's more welcoming of international students from your region. If you are in Asia, consider a higher-profile nearby Asiatic country. If you are in Europe, consider a different part of Europe, etc. There's lots of wonderful places in the world outside the US - and many of them are even known and respected in the US, too.
Apply to places that aren't so swamped with international applicants. Smaller, less internationally recognized state schools and private institutions will be less likely to have insane amounts of applications for a tiny amount of available seats. Institutions that are advertising that they are expanding their programs or creating new ones may be more risky in some ways - they don't have a proven track-record of success - but they will also have way less applicants to chose from and may be more flexible in their admissions criteria (or at least have more time to look at each candidate more deeply).
Consider "getting your foot in the door" by actually applying for an undergraduate degree in the US, either more general or more specific than your previous one. You may prioritize "feeder" institutions where you will have the opportunity to meet and/or work with people who make decisions on admittance to graduate programs. This way not only will you get rid of the problem of not being from a recognized school/country, but you can also work yourself into being a "domestic" applicant AND having earned your own social connections and recognition to help aid your future applications.
As with going for an undergraduate degree in the US, you might also wish to target places/programs that have good industry connections, as if nothing else you can at least leave academia with professional interests in the area of your passion and in a place where there is demand for your skills.
Seek out international campuses/extensions of US institutions. These can be ultra-competitive too, but not all are - and they come with a built-in connection to "brands" that are valued in the US and Europe, and there is the potential to make international connections with the home institution.
Finally, reconsider your existing credentials and professional outlook - with a specialized degree, often job opportunities are very regional-specific and not well advertised. This is true everywhere - here in the US I lived in a place where there seemed to be 2 total positions for my professional skills, while 150 miles south there are a dozen companies who are getting into a bidding war for candidates because they can't find enough qualified people!
No matter what you do, I hope you realize that no path will be easy, and neither does any path - regardless of difficulty - guarantee anything related to success or even happiness. In the US alone we have more people who commit suicide than die in traffic accidents - over 30,000 per year choose not to live any more. Even if you get what you want and even if you decide to move to the US or any other country, there are people who are unhappy there too, regardless of even if they were getting what they wanted.
Your journey will be whatever it ends up being - this may include going to another country sooner or later, or not. What you've achieved already is proof that you are capable of a great deal, and surely that you also are capable of even more than that. Don't accept only a single isolated path as The One True Way - be open to other options too, so that you get to chose the best option, rather than just end up with the only one that ended up possible. And so in this you won't ever give up - only choose the option that seems to be the best, even if that was not necessarily what you had originally planned!