I just think it's unfair of her to leave you hanging like that. On the one hand, she claims breaking up with you could be one of the worst mistakes she ever makes. On the other hand, she's not willing to try to work things out together before giving up on the whole thing. I don't know if she's just being nice with her words, or wants the best of both worlds. But it's like she wants you to wait around for her, but doesn't want to have to make you a priority in her life. You're not in the first few months of dating anymore, and it's impossible to recapture that. If you don't want a relationship that will forever be stuck in a "just dating" phase, then I think breaking up with her is the right thing to do. I wouldn't try to keep seeing each other casually because that's likely to make things worse. Do your best to move on. I hope things improve with your mom.
“This planet has - or rather had - a problem, which was this: most of the people living on it were unhappy for pretty much of the time. Many solutions were suggested for this problem, but most of these were largely concerned with the movement of small green pieces of paper, which was odd because on the whole it wasn't the small green pieces of paper that were unhappy.” ― Douglas Adams, The Hitchhiker's Guide to the Galaxy