Did this girl use me?

[Stacie Danielle]

I agree with jane. I'd also say yeah, you've been used. Unfortunately people like her will need someone to soak up all the problems so she doesn't have to. The snide comments will be, like you say, to make herself feel better.
You're a good person by the sound of it. Stupid for sticking around bit you won't go for someone like that again I'm guessing.
Stay strong, you're worth so much better than being used.