I need help, my life is too hard to bear anymore?

This is going to be kind of complicated to explain... sometimes I'm really happy such as last night when people in my colour house performed in a festival. We lost, but it was still alot of fun. But today I was just miserable... I just wanted to cry so hard, but I bottled it up inside of me. I don't see a future for me, I don't see a life, No one understands me and no one wants to. I'm so scared that I'll start mutilating myself again, I feel that I am losing touch with everyone in the universe. My 'friends' kind of look down on me... they think I have no imagination just because we share different tastes in film (and I'm 100% fine with that) Family life is horrible... my little brother who is 15 just bullies me all the time and says some sexist remarks. But my parents are like 'its little brother behaviour' or 'that's what siblings are doing' but they've seen my brawling my eyes out, the cuts on my arms and thighs. I'm so stressed out about school, my teachers don't get me, no one gets me, I don't see the point in anything anymore. I see my school councillor, but whenever I want to talk about my thoughts she just changes the subject and it makes me miserable. I hate everything in my life, but I don't want to hurt anyone. What's the point in leaving school and getting a job and starting a family? I can't play sports, I'm so fat and my diet is pathetic, it's just peanut butter on toast and pepsi max that's all I ever eat. It's so hard to sleep, I have to wake up early in the morning to catch my bus, I'm always tired. I feel like a failure and a gigantic loser. I don't know who I am and what I believe in, but its probably nothing special. I hate everything, but I don't want to. Please help.