Holy shit I cant believe they did that! I would be so pissed, you did nothing wrong then they lied to make it worse, FUCK! Try and get someone else on your side. Try the school counselor, explain to them what is happening and maybe they will side with you or at least agree that something is not being handled right. Destroy the system from within! If that doesnt work talk to other adults who can help. Maybe you can get a professional psychologist to step in (not that you need one, but maybe they can help since they are kinda obligated to do something). Talk to your peeps if you havent already. Get some help from the students, may not be too effective but it could help. Also if theres a teacher you know that doesnt fuck with you talk to them and get their help. Get the help of anyone who will listen, it can't hurt.
Anyways for the last 2 weeks I felt the same as you, trapped. I couldnt talk to anyone, couldnt express my feelings to anyone, couldnt even do what I feel cuz I knew it would fuck some things up. Well a few days ago at a party I was just trying to forget everything so I smoked some mad weed. I stepped in and did something right that helped out a few ppl, although this got one of my best freinds mad at me enough to want to kill me. A lot of other big problems came out of this but I know that things are how they should be. The fallout of this party sucks, I realized a few things that I should have a long time ago, I lost a good friend to that fight, thats not all tho. Still Im feeling so much better. Im not saying your going to have an opportunity like this that turns you around but it will get better, just like everyone in this post has said before. You will get out of this shitty school, you will meet new ppl, you can make a change to whatever you want in the near future. For me it sucks right now, I have 1 of 3 really good friends left, and hes never around. My lifes going to be a lot different. I still havent totally gotten over all of my problems, that will take time but things are getting better slowly.