Firstly, you donot have any problem with your mind. You are completely normal, just that you are overly stressed.
The main reason students are unable to academically preform is due to mental constraints they themselves create.
In your example, you have some thoughts like , coaching is necessarry to get into neet, but you know you cannot go to coaching due to your situation. But actually, no, coaching is not a necessity at all. well, it can give you an edge, but I can tell you that it is not necessary from my own experience.
The main reason you cannot study is because, your mind wants to do something else. But when you do something else, your sense of responsibility tells you that studying is imporatant and so, you go back to study.
So, here is what you should do. First take a small break, for a few hours. Think about what you like to do the most. Then do it. This will help you clear your mind. The next step is think about yourself and your situation. Think how important you are , and how important your dream is, and slowly try to set all other things aside and concentrate on studies alone.
It will be difficult, but once you understantand studying is more important, you will automatically start studying. The main problem is that now you donot have much choices. Your only aim is NEET, and you are bored from inside. So, try doing something more interesting. Not having social media is good, but try having friends, someone to talk to...maybe your own family members, your mother, sister , or someone else.
Now this state of mind is the mind everyone has, when they get bored of doing same thing repeatedly. So, study using different methods. You can try walking while studying, instead of sitting somewhere idle. OR develop some reading habits. Read something interesting , but related to studies, like some intersting facts, when you get bored. Anything that can take your stress away. Try these,and you will surely do better.
BEST OF LUCK and HAPPY LEARNING!!!