From my perspective, after reading your question, it seems to me that the source of your anxiety might be a deep lack of self-worth (which can be solved over time, with effort and determination). To be more specific, you have created an identity of yourself as a researcher, and it is clearly an identity that you are deeply passionate about, but you are also very afraid that others might challenge that identity, and destroy it.
In your mind, the success of papers and grants is an absolutely essential, fundamental aspect of your identity as a researcher. That is, you are deeply attaching your worth and value as a researcher (perhaps even as a human being?) to the results of your paper. Perhaps you are worried that, if this paper is not accepted, and you cannot find any idea for pushing the paper forward towards acceptance, then you have fundamentally failed as a researcher, and if that identity fails, you might not have any backup plan for an alternative identity.
Of course, these assumptions that you hold about your identity and your worth as a researcher are clearly mistaken, and perhaps you already suspect that this is the case. Nevertheless, your anxiety is still holding a grip on you, and you are hoping that someone else can bring some clarity to your situation.
First, let us deconstruct your identity. In other words, let's make it clear that you are not your clothes, you are not your car, you are not your house, and you are not your wealth. If you don't have a certain car or a certain brand of clothes, that does not mean that you are worth any less as a person. In the same way, you are not your research papers. Your worth as a researcher cannot be defined by the success of your papers. And if you doubt this, just ask your colleagues and everybody else in academia about the multiple times they failed to get a position, got rejection letters, failed to get grants, and failed to get papers published. All of us have a long history of failing, it is not just you who is facing this issue. This is a universal experience in academia.
The challenge I want to propose to you is: can you be at peace with failing, even if you tried your best? Can you train yourself to dissociate failure from your sense of self-worth? Perhaps, can you train yourself to love failure? If everybody around you told you that your work was not that great, would you still feel passionate enough about research to continue regardless? This is crucial. Nobody can force you to gain a sense of self-worth and find internal strength to deal with regular failures. No matter what other people tell you, no matter how much they try to comfort you, ultimately the only person who can strengthen your mind is you. And this is achieved by telling yourself, everyday if necessary, that it is alright to fail repeatedly.
People who have succeeded in academia have trained themselves to think that, even if they fail one time, two times, three times, four times, it does not mean that they will fail a fifth time. History is not destiny. Furthermore, they have trained themselves to understand that in most cases, there is usually a second chance, and even a third chance. The important thing to do after each failure is to first get a good night rest, do something that helps you to calm down, find some comfort and laughter in a good comedy show, and once you have reestablished yourself mentally, you must start to discuss your paper with trusted colleagues and start elaborating a step-by-step plan to fix any problems with your paper and move forward with a positive attitude.
Please understand that, no matter how good you are, you will always face attacks and criticism by someone. Even the great minds of science have had to face repeated attacks by colleagues and society at large. Can you be OK with this fact? Can you be at peace with this and move forward with joy, no matter what? Can you accept the idea that the challenges will never stop coming, no matter how good you get? Instead of looking at the waves at the sea as your enemies, as something that you should be afraid of, can you try to ride the challenging waves? And if you fall from your board, and the waves hit you strong, can you get back to the surface, and look forward to riding the next wave with joy and anticipation? If you can train yourself to do this every day, then you can defeat the tendency of your brain to automatically cripple your energy and enthusiasm. Remember that all of us, no matter how famous, are all facing the same waves, and often failing to ride them.
Of course, even though everything ultimately depends on you, I still advise you to seek the counsel of your close ones and counseling from any experts on mental health issues at your institution, because you should seek all the help you can get. Just don't use them as crutches, or excuses to prevent you from doing the hard emotional work that needs to be done. And this hard work is the following: every time you get criticized by your superiors in public, every time your paper fails, every time someone attacks you, every time that research is not progressing smoothly, do your best to stay strong and balanced, and repeat to yourself: it's alright, it's OK. My self-worth does not depend on being successful every time. I am much more than just a researcher, I am much more than my nationality or gender, and I have value as a human being, no matter what happens. I will take a rest, get myself back in shape with a few laughs, and find a new way to address this issue with the help of my colleagues and close ones.
No matter how good you think you are, it's always possible to do a little better next time. Just keep trying your very best, and even if your effort fails, do not be hard on yourself. Always tell yourself that you did the best you could at that time, and that you will devote yourself to doing better next time. In order to survive as a researcher, you must value yourself and cherish yourself at all times, and once you get yourself into a stable emotional state, only then you will be able to face the constant challenges.
To conclude, what defines a successful researcher is not how many times they are successful, it is the way in which they gracefully deal with defeat and failure, and continuously seek ways to bounce back, and try to keep their passion for research alive and strong.
Do not be discouraged, and learn to let go of the paper's results. Try to get feedback on the paper from as many trusted people as you can, but at some point, you need to finish the paper, and offer yourself as a "sacrificial lamb" to the opinion of the journal's reviewers, with courage and dignity. No matter what the result is, in most cases there is a path forward, it just might take a few good rounds of busting your brain and rethinking your approach. Stay strong. You are worthy of being appreciated as a researcher regardless of the results.
My apologies for the long answer, but I felt your situation deserved more than just a few kind words of support.