Beth,
Welcome, glad you found us. Sorry for the pain your mother has caused you. Yes sometimes we have to step away from our addict, to protect ourselves. They say that we need to put on our oxygen mask first.
I would also recommend alanon or open aa meetings. Have you tried an addiction therapist for support? At some point you realize you can't save her, but you have to save yourself. Work on you, and your life will slowly get better, for her, I'm not so sure.
Keep posting, and reading all over this forum. There is a lot of knowledge in these walls. Hugs my friend, we do understand what it is like to love an addict.