i'm really bad at sport what can i do?

It doesn't sound like you even like to do sports, so why care if u suck at PE. First advice would be to stop caring about what other people think of you.
I'm sure you dont do all sports at PE and theres a sport for everyone. A friend of mine sucks at all ballsports, but he turned out to be pretty good at rowing. I can't shoot a hoop, but i am a decent soccer player. Most important thing is to just have fun, sports are not always about winning or being good at it.

I was a professional musician for twenty years. People would ask me how I got to be so good; I would tell them it was because I was useless at football. And cricket, and rugby, and swimming.
People are often good either at using their minds, or at sports.
PE teachers are notoriously bad at coping with pupils who are not good a their subject; often because they themselves aren't good at anything else.

It is difficult. But it will not last for ever. Try your best, and you have no reason to reproach yourself. You may even find one activity you like. (I found tennis and horse-riding eventually!)
Try talking to your teacher; they will appreciate it if you say you want to do your best.