I just want to disappear

I’m 13 year old girl and in 7th grade. I’m a loner and I’m very depressed. Everyday I have to go and come from school. When I come home from school all I do is yell at my parents and cuss. I have never been thankful for what they bought me and did for me… All I do is make them sad and angry. When I don’t get the things I want I yell at them and then we quarrel. After that I go in my room, shut the door and cry. I realize how childish and greedy I am but it’s not just because I don’t get the things I want, it’s mostly because I don’t have friends and am a loner at school. Because of that I only spend my entire time home in my dark room playing at the computer, reading Manga, watching Anime or Korean-dramas and listen to music. I have a few friends at school that I can’t even call friends. When I was little I didn’t go to 2nd grade and was directly transferred in to the 3rd grade. I should be in the 8th grade right now but instead of being in the 8th grade I end up in the 7th grade because I didn’t know any math and got marked-down a grade. But because of that I got a few friends but that didn’t last very long… We are still friends but only at school. Last year we all were in the same class but only I got into a different class. Now they are all great friends. I only get to see them in the lunch break and in french lessons. They all go to each others homes, only I don’t. I’m the only ugly and stupid girl in my class. I’m basically the loner of the whole class. Because of that I get depressed everyday and give my anger out on other people. I wish to die but can’t kill myself. I wish something bad would happen to me all the time and I cut myself because I feel better if I do that. I don’t tell anyone about this and when somebody is kind to me I feel disgusted. I just wish to disappear and wish to have never been born. I find myself a disgusting, ugly, stupid and greedy girl who doesn’t even thank her parents for the kindess they gave her all these years bringing her up.