I'm sorry you are going through this. It sounds like a very painful situation for everyone involved. Yor mother probably means it when she says she loves you, but is too messed up to truly understand what that means or act apropriately.

You have done everything you can to support your mum and she has not been ready to accept that support. You owe her nothing more- she is responsible for her own life. Until she is ready to take that responsibility, the relationship will remain toxic for you. If you are not comfortable cutting her out of your life entirely, you might try limiting contact to sending a card on her birthday and holidays. This leaves the door open to a future relationship with her if she decides to make some changes in her life.

I hope it works out between you and your mum. Regardless of how it turns out, you will find supportive people here who can relate to yor problems. Welcome.