If you want to talk or anything at all; my PM is open
If you're under 19 call childline (08001111) or use their online instant messenger.
Keep your chin up, try to be brave. It's going to be okay.
I can understand why you may not want to report it, so you might like to try talking to your dad about it first and see if there is anything you can sort out. Maybe you could arrange with your dad and basically tell he you will report her if she doesn't let you go live with him.
If it's a divorce situation and your mum has legal custody though you may have to report it so custody can be changed.
If you have siblings I suggest you report it or makes sure that you are all taken away from your mum to make sure they are also safe. Even if she doesn't hurt them at the moment that may change.
To report it you can call 101 (non urgent police number) or talk to your school, doctor or dad so they can help you. You can see a doctor without your mum.
You can also google it and visit sites like Childline for advice. Here's a link that may help https://www.childline.org.uk/info-ad.../abuse-safety/
Please feel free to go into more detail, ask questions etc. If we know a bit more detail we may be able to give you some better advice.
This is not something you should be going through at all and certainly isn't something you need to go through alone.