Friends, depression, weight..

Hello, I'm 17 and am deeply in depression which I have to cure by myself since my parents don't believe I need a doctor even after 4 years of self-harm.. I have lots of problems that I desperately need advices with. I don't have friends and ones who call themselves my friends treat me like god - they come to me only when they need me. I'm very overweight and can't lose it normally, only time a diet worked I was on edge of anorexia and as soon as I got rid of the problem I became a blob again. I need advices what and how to do. I'm a weirdo at school, tomboyish and different. I love metal, black clothing and prefer not to wear makeup. I started failing my clases too, not because the stuff is too hard for me, but because teachers hate me since I have to correct them very often. I feel suppresed and forced to do stuff that I just can't or aren't for me. I also hate this place and can't wait to move to somewhere else (I'm from Croatia and moved to Germany 3 years ago my dream is to go to Ireland). I'm very sorry if all I wrote so far made no sense at all, but I finally cought a little courage to go ahead and do this so I'm doing it as fast as possible. Please help me, should I get professional help to sort this all out or? How to deal with all this?