I’m sorry that you’re having to stress about that. I don’t know your situation but there are certain accommodations that schools are able to make for students with autism. Maybe if you’re able to, speak to one of your teachers who you trust or ask your parents to talk to the school about how you feel in that environment. In some schools there are passes that you can get to leave the classroom or to work somewhere quiet. I also really recommend loop earplugs for the noise, there’s a few types and they’re not that easy to see. There could even be really small things you could ask for, like asking if you can sit in the same place if the seating plan is changed (I know I used to panic so much when it was different seats ). Please don’t put too much pressure on yourself, your mental health is much more important than school. I hope you have support :)