An answer to your plea for advice:
I'll say this: as a teenager, it's your priority to focus on education for your future. If added pressure from the people that you thought were your friends is stressing you out and distracting you from your studies, do exactly what you plan and end your friendship. It's not called abandoning them if you explain to them nicely that you don't want to be friends anymore and need some alone time to recollect your thoughts. If they're not being considerate of your feelings and you don't feel like you can trust them anymore, it's perfectly okay to stop being friends. Things like this happen all the time; friendships just don't work out and you want to end your relationships with them just to lessen the hurt for both parties.
Thanks for reading my story, by the way, and I wish you the best of luck. :D