Why can I not get over it totally?

So, just recently I reconnected with this girl I used to work with a few years back.

We hung out once or twice and really hit it off having a marvelous time. So I asked her out, in which she replied yes, and how much she would love to.

Well, the night before we were to go on a first date, she texted me to apologize that her best guy friend of 5-6 months that she has really liked admitted he liked her and wanted a relationship to see where it could lead to. In which she accepted and cancelled on me.

I was upset at first but cooled down a bit and tried my best to understand, and because she commented how much she cared for me and wishes that we could still talk and hang out.

Well a few days later, she called me crying about how her best guy friend refused to talk to her after I guess she lied to him via text, and she kept commenting about how she needs someone like me who was always patient and how stupid she was (blah blah blah... I didn't fully listen as she was a bit drunk and I could tell the situation wasn't as bad as she thought it was)

Well next morning she and him made up, and so on.

All that is just a back story, the question I have though, is even trying after 2 weeks, I cannot still fully get over her, even though it never got serious. And I don't know why. any suggestions?