How do I get away from here?

Iv had enough of being walked all over in my house . My mum my dad an 21 year old sister all gang up on me and attack me all the time . I'm 15 I don't want to live here iv had enough. I don't see the point an being here if my life is just to be lived like this. How would I get put into care . Iv tried speaking to people I'm not getting anywhere can you help me?