I feel depressed.. Can you help?

I've never been depressed. I'm an honor student at school, I have a loving group of friends, but I dread going home to mother. My brother recently started living with us because our father threw him out, he also threw me out for literally no reason except me calling him unfair. That made me very sad. But my brother is my mom golden child even though he does horribly academicly. Today we had a big fight and I went to my room and banged my head on the wall. She then came in and started yelling at me and hit me with a feather duster end (the plastic part) leaving a mark on my arm and leg, but nothing serious it is not child abuse. She then proceeded to tell me that because of me her and my stepfather are going top split up and I said I wanted to be in a group home to be adopted then she said no one would love me enough to adopt me and thats why my dad threw me out. My birthday is in five days and I am going to turn 14. I am a girl. Sorry for the misspelling, I am crying at the moment. I have thought about running away, suicide but I know those things are idiotic. But I really feel I have no use in this world. I don't want to live.