Well thanks for the input guys. No, bad sex definitely wasn't the issue.
I sent her a valentine's day card (anonymously, but she guessed it was me). I told her that I was dating other girls but to give me a call if ever she changed her mind. Funnily enough we are talking (well, texting) a lot more since. I said I would love to take her out again sometime so that'll probably happen next month.
She is still very much in the not wanting a relationship mindset but at least now I know it was nothing personal. I know that she hasn't seen/isn't seeing anyone else. Anyway, I'm happy dating around and not getting exclusive with anyone just yet. I'll remain friendly with her, but not close friends, so she never sees me as relationship material again. I'm happy with the way things are at the moment, if she wants to get together great, if not, fine. I'd still like to see her every so often, she didn't object to that proposal
