Hi there
Firstly I would like to say that you have done the right thing already by speaking out about this. Your mum's behaviour is not acceptable.
Sometimes when young people get hit they find it difficult to talk for many different reasons. By talking about what's happening to you can help to stop abusive behaviour from happening.
At ChildLine we have counsellors who are trained to help you with this and who you can contact. If you either phone 0800 1111or login online and have a 1-2-1 chat together with a counsellor you can work out how to stop mum's behaviour.
It sounds as though you recognise that this is something that should not be happening.
Also take a look at the ChildLine message boards to see what others may have tried when something similar has happened to them.
Hope this helps and take care
Sam