Unsure about who she is

So I have been seeing someone for 7 months. We split a little over a week ago.

Before this, even though I knew she had issues, we seemed really close. Things seemed to go well and we never argued. Then in the week leading up to to splitting up she was quite cruel in some of the things that she said. Then she messaged me to say it was over, she still said some cruel things during that message. In all honesty, I have no idea where it has come from because she had never been like that previously.

Since that point we have continued to talk but she goes between being really nice and complimentary to being extremely cruel in her words and I have no idea what even provokes this. Like I said, it was never like this before and then in a week or two she has just changed completely.

I know in past relationships she has been quite controlling of her partners and even in ours I would do nearly everything for her, but in our relationship I was ok with that because everything was peaceful and she was happy. So I suppose I am just looking for some advice on what to do. I don't know if getting back with her is going to be an option, and even if it is I don't know if I would want to because of all of this. Did I really know who she was or is who she is being now who she really is? Or was I just blind to it because I loved her?