Confused

I just don't get it?! I'm friendly to everyone. Even people I don't really talk to but I guess I'm just not meant to have friends. I have people that hate me when I don't say not one thing to them. I'm quiet at school most of the time and I usually never talk to anyone. I honestly think the reason why some people don't like me is because of this one girl that keeps up drama with me & will tell lies to be popular. She tell them lies about me which changes their feelings towards me which is stupid if you ask me. I try to ignore what people say about me but I'm the type of person that will pop off if the situation has gone too far & that it has come to where I don't care about anything anymore. I think too much about what people think. Someone could just look at me with a mean look and I'll think to myself why they don't like me. I hope someday, one day i will finally learn how to forget about what people say. Could anyone give me some advice on how to forget about what other people think/say about me?