How Do i Get Out Of Bad Enviroment?

Me and my family are having problems. My step-brother keeps fighting with my family, by family I mean me, my parents, my sister, and my brother. It's getting out of control, It started with me getting a dog and my step brother hating it so he argued with my dad and told him off about it. Weeks later more arguments and more and today guess what more arguments with my step brother this time it was with me.

I'm only 15 there so much a teenager can handle but I just can't handle it no more. I got out of control that I hit my step brother and I threw water at him.my sister was arguing with him also. I just can't handle it no more I was in my room 20mins ago contemplating suicide sometimes I feel emotionless I know if I get in another heated argument with my step brother it will end bad either me ending up in jail or worse I don't want to be in this environment no more. I have no where to go.

I am getting help with therapist but it ain't working my dog has help with my depression but everyone seems to hate him my step brother said he's going to take that dog away from me too bad I don't have papers for my dog my family wants to move but we have bad credit so we can't get a house
any advice how could I get out of this bad environment before I go insane or advice how my family can get a house or apartment with bad credit?