She started it...?

I used to work with a girl who I considered one of my best friends, she quit and then went out of town for a week. Which was fine, and then she came back and started getting upset that I was working so much and not spending time with her. She started sending me text messages about "the good times we used to have" like we were ages ago. And then on a night when I got off early, all I wanted to do was go home and see my daughter (I would like to add that I work in a very stressful environment and most of the time when she talks it's all about the drama in her life) and I told her that.

Somehow it started this "what did I do to you?" that I just didn't understand and I told her she didn't do anything, but then she started calling me really horrible things, and I fired back.

It ended with me saying that I was done with this and I turned off my phone. Now she keeps texting me that she wants to talk and she doesn't want it to end like this and I really don't know what to do.

Help!