What should i do?

Ok,
So im having really big problems at home. My mum had a kindney transplant and before that I use to clean and cook, babysit my nephew and still went to school. Since she had the transplant all we have done is fought, about 5 months ago I left home and...

stayed at a mates, then mum and dad came after me and talked me into coming home by saying we will change and stupid me belived it...
When I came home it changed for a while and then it went back to normal, the abuse and the just everything!!
I am only 14 but I have grown up so much faster then my mates. I am more like a mum to my nephew then an aunty, I look after him and all the things my parents should do. ( he lives with us not his mum )
My mum is cheating on my dad and I know it because I saw the txts on her phone from her ex boyfriend. My parents were happyly married for 9 years but thats all changed since the transplant. My dad has always hated me and I dont like to be around him with out someone eles because im scared of what he will do.
In feb my mum is going to away for about week and im thinking about running away the first day she is gone.
The only problem is that I dont wont to leave my nephew behind because I recon that my dad will hurt him with his drunk rages. So I was thinking bout taking my nephew with me. I have a safe place to go to ( really ) and I would feel safer there then with my dad. My nephew is 6 and im 14 and I know that will be illegal and that my dad, mum and police will be after me if I do run but what eles am I surpose to do. I have $529 saved and another $149 coming in the bank tomorrow. What do I do?? the only person im worried about hurting is my mum because 2 of her other children left when they were 15...
What to do?

I say if you hava safe place to go then go b/c your dad doesn't sound like the type of person to really care if you leave...Not rying to be insulting either sorry. But if he's an alcoholic or wutever he'd probably not care if he's been drinking

You really need to talk with your mom. Tell her everything you just told us - how you're afraid of your dad, cheating. Well, not the cheating if you don't want. But just talk to her and see if you two can try and fix things between everyone. What might make it a little better is by doing different chores around the house. Maybe you have a messy house and that's what's causing your mom to stress out? Just talk with your mom!
Funmail me if you need anything.

It's better to be from a broken home than in a broken home. Maybe what you need to do is go to someone of authority, because taking your nephew could get you into even more trouble. And, that's not what you want. This is going to sound really Sesame Street cheesy, but try going to an adult that you trust that isn't friends with your mom or dad so that they won't have an altered opinion, and then take it from there.