Why do other people think they are better than me?

So I am 17 and in high school and so may people in there are really rude to me and think that they are better than I am and I am a really nice person and kind. I have several disabilities and issues and I get people being mean and picking on me. I was told that a of of people think that they are better than me. I have low self esteem and confidence and I'm depressed and a introvert and I get a lot of people taking advantage of me. I never stand up for my self in fear of getting introuble by my parents. I never understand mind games so people can take advantge of me and be mean to me whenever they like. I am really sensitive and cry very easily and I don't know how to deal with this. I have been verbaly abused and teased all my life and I want it to stop. How do I deal with people who think they are better than me? I feel like I am the only one like this. Sorry for bad spelling was on a mobile yahoo answers.