Flaky girl come back?

[Nighnogh]

So I've had this weird on and off relationship with a girl. At the beginning it was really cool, we escalated all the way to sex but then things began to get weird. One day I proposed we should talk over a couple of drinks and she seemed to be good with the idea. The day we were supposed to go out the girl flaked out a couple of hours before but she told me to call her the next day, so i did and she didn't answer. Next weekend she said she'd make it up to me and set up another date, but when the day came she flaked out again. I figured she wasn't interested so I decided to move on. I stopped texting and started doing my own thing etc. Today she sent me a private message through facebook saying: "Hey I have the feeling you're mad at me or something, how about those drinks?" How should I react to that? and why is she doing this?