Best thing you could do is to change your school but if its impossible, try to make ur self happy in other ways (music sports etc) distract yourself from thinking stuff that you don't wanna be thinking, and time will heal this problem.
I had the same experience ( year before)and same way , being 22 and stilll not matured enough but now when I think about it I get only 10 % of feeling I had at the beginning (more than a year) .
What I did was read books like -see u at the top- think and grow rich - etc and watched many motivational videos including Leo's actualisation stuff , doing these things helped me to get back to real world problems I had or else I would be still studying and wondering what s gonna happen next.
This is the best time you can invest on yourself make a turn to the direction you want yourself to be .
If you listen to music stop it for a while , I stopped and the only thing I listened to was "nothing else matters " by Metallica and that one song had all the spirit to get me back to the right direction.
Good luck !
