I was enrolled in a prestigious school in central Europe, studying an MSc in computer science.
I have decided to drop out because it seriously felt like my bachelor background was weak, and I had to cover too much ground. Also, my study technique was poor.
Will it be possible to go back to graduate school if I want to again in future?
Yes, it's possible.
The only thing you will need to consider is how to explain why you dropped out on future applications. A department or university will need to be convinced that you won't simply drop out again soon after starting the course. Before reapplying, you should think carefully about how to demonstrate that you've solved the problems that caused you to drop out before, perhaps by self-studying or taking online courses so that you are better prepared.
Possibly
but it sounds like you haven't officially "dropped out" yet, so there is another better option if you'd like to return
Take A Leave Of Absence
Most universities offer students the ability to take a semester to a year off and return without reapplying. It's usually referred to as a Leave of Absence. You'll have to talk with someone in the administrative office of your university, and possibly someone in your department.
It's more common than you think. Some students do it to deal with medical issues, but many do it for the reason you're considering dropping out. Getting a degree can be overwhelming sometimes, and if you're struggling early on, sometimes a break can help you re-group and catch up.
Universities understand that sometimes a student can get overwhelmed, before dropping out, see what other options there may be to give you time to catch up and improve your study skills.
You can probably go back, but...
How will dropping out improve things? It sounds like a poor approach unless you have some positive options to make your situation better. How will dropping out improve your study skills, say. It won't improve your already finished undergraduate degree.
People do leave and return. That isn't a huge problem most places. But when you want to return, people will ask you about your suitability and the probability of your success.
Let me suggest you think about whether staying and working on study habits and work process isn't a better path for you than leaving.
Of course, you may have other reasons that you don't state here that make leaving for a while a better plan. But if you go, have a plan, not just a hope, for your return if that is your intention.
