Bad relationship with my mother

I'm sorry if this is really long but I need to get it all out.
I've always had a bad relationship with my mum to the point it's almost driving me insane, I have this anxiety attacks and I'm so depressed and she piles on pressure and goes to teachers saying they shouldn't be encouraging me to drop subjects and they're not helping me.
I've had social services get involved but being from an Asian background, a pinch from my mother and a sentence in a threatening tone shut me up to pretend everything is all happy families.
She threatens me for everything and my brother, something simple like if you don't start your piano practice in 2 minutes one of you will get hit.
Her response to everything is you'll get hit, you're asking to be beaten.
I completely broke down at my sch today in front of all the teachers and literally the whole student body and she goes WTF IS WRONG WITH YOU YOU'RE EMBARRASSING ME.
We talked to someone and they were like you can come to me for anything so I asked about fixing a problem at home and my mum pursed her lips and said are you crazy and did the whole she's crazy pointing at her head thing and said it's nothing to do with them, you don't ask this stuff and so the teacher who I could "come to him for anything" left and said I'll let you two deal with it.
Each year I hate my mother more and more and I can't do anything, defying her makes things x10000 worse and the consequences are horrible I can't go to anyone like police/social services because this would be a huge impact on my brother.
I can't move out, she'd track me down and I attempted to run away once but I can't abandon my brother and also received a beating when I got home.
I have no idea what to do and I can't get any help that would affect my brother