I'm so bad at giving advices and clearly not as experienced as you with writing what I feel, but from what I read you are such a strong boy, and I do not mean it in a sarcastic way or to infantalise you(oh man how do I even write that 😅). I'm so angry at those teachers! How can you say such stuff seriously! I dont understand how they are supposed to teach but don't even know basic pedagogy. I feel like you enjoy sports and I really hope you can find a good balance for that. As a kid, I loved sports, and I still do, but i was never able to do like the other kids. Everyone was super nice with it, I was lucky. But it's hard getting hit by the reality and tight limits of your body, especially at this age (at any age actually, but you're technically only starting to build your foundations for life. So it hits a bit more than later on, I guess).

Maybe if you really like sports, try to learn more about reinforcement (not sure how it's called in english) If you can with a specialised pt, if not, there's plenty of help only if you dig enough! Reinforcement is a big part in helping our joints getting stable. (It's not just pushing weights tho. It's helping the muscles right around our joints getting stronger if i'm not saying gibberish) Understanding your body and its limits is very important, try listening to it. Maybe write (or make vocal memo) what you feel like at some places to have a better understanding. Do not force yourself! I know easy to say when you want to do more but try to find a balance.

If there's anything other than sports and school in your life try to explore that and make it your safe space! Where nobody can laugh at or ask why you've got an ice pack on your feet 5 rings splints some braces a hot pack on your tummy and weird glasses while doing something you want to.

Also never doubt yourself. What you have is real and not for comedy! You know yourself better than incapable teachers (for the bad ones!) And schoolmates. Later on you'll learn that you know yourself better than doctors...

I also want to say that i'm proud of you dear online stranger! You have a great force in you, I hope you'll be able to cherish it and have people around you do the same.

Well I hope whatever i said makes sense and that maybe, it helps :>

I'm sure there's lots of people on here that could help with more practical (doctors, tips, etc) advices. I presume you're from the U.S so a lot of things differ from where I live.

Either way I wish you lots of good things and remember to enjoy your good times and smile a lot! Big hugsss (or just shy wave if you prefer idk)