Is it normal my mum is like this?

Okay so this is probably going to be a bit long but bare with me. As a kid I was raised by just my mother, however she always used to swear and yell at me and hit me. When I turned around 7 my mother gave me up for my dad to raise me but she's been complaining about it ever since and says that my dad stole me from her, even though she was the one that gave me up.

My dad treats me pretty okay, we aren't extremely close and sometimes have disagreements but we get along mostly. My mum keeps trying to guilt trip and manipulate me into living with her though, she says she misses me and cries every night, yet when I do sleep over on the weekend she acts like a total bitch to me and says she never wants to see me again?

It's gotten worse since I've just turned 18, she swears obsessively and gets drunk, which is when she usually harasses me and calls me names.

I've tried stopping contact with her, but she pleads and begs me to see her and I do it just to get her off my back, because she also harasses my dad.

My mum also thinks that because I don't want to live with her, that me and my dad are in a sexual relationship which is fucking disgusting. She's threatened to call lawyers or some shit and she says that everyone she's told think my dad is doing things to me, and I'm over here like the fuck? My dads never done anything like that to me, he has a fucking girlfriend for gods sake.

I just fucking hate going to my mums place because her mood changes so quickly, she could be fine one minute then a second later going on a huge rant on why she hates my dad or calling me a bitch.

It's emotionally draining being in her presence, but I can't stop contact with her because she'll throw a huge fit and find someway into trying to make it up to me just so she can hurt me again. She thinks she has control over me and that I should always listen to her because she's my mum.