I'm sick of being obsessed with what others think of me?

I'm 13 years old and I'm all ways trying to be perfect. I live in a small town and people in my class are really judge mental, so everyone is obsessed with what others think of them. There are alot of fakers in my grade, There are only a few real people sprinkled in there. I'm allways trying to be perfect, look perfect, act perfect, etc. because Im so scared of what people think of me! Its making me stressed out and my grades are dropping. I want to not care what others think but its hard. Any suggestions. sometimes i just want to cry.