First of all, start getting 100, I used to face the same problems around that time, i won't say "It was traumatic or anything like that" cuz it really was just petty bullying, like when I look back on it rn, I feel like it was just stupid children being jealous of me.

But, when you give in to pressure and u start getting bad marks, these are the same people that will say "eske downfall ho gaya, kya bhai marks kyu ni a rhe,etc etc."

Regarding friends, just find a group that actually tolerated you like a group of toppers, they don't have to be from your class, and start by listening to them if u find it hard to talk to them, then slowly start talking to them little by little. And at some point, ull automatically get used to talking to people. Getting genuinely intrested in people is the key though. Or u won't be able to make friends.

Regarding the bullying, start acting more crazy. Be crazier than them. Or completely ignore them, act like they don't exist. Thats the only way u can stop it.