Well it's over with her. The other guy she was seeing asked her to be official and she went with it.
I know I'll get over it pretty quick but I still feel like shit. You always start wondering what you fucked up. In talking with her, I really should have asked her what was up with what appeared to be flakiness way earlier. Instead I just assumed non-interest and let it go.
I'm not saying anything would have turned out differently if I had asked her about it, but it would have been one less question mark.
I'm taking this as a learning experience. It's been a while since I've been in any sort of relationship and I let my happiness at gaining the attention of a sweet, beautiful girl overrule the nuts and bolts of making a potential relationship work. Basically, I invested too much and didn't 'call her' on something that I should have because I was afraid of losing her. If calling her on it resulted in things ending, well that's where I am now any way, and I would have saved a couple months of time and some emotional stress.
This experience has also restarted my engines so to speak. I never put much effort into approaching girls, but if I could attract someone like this girl while putting literally zero effort into it (ok, I asked her if she was feeling alright, that was it), then why not? It was fun while the good times lasted and I figure more experience leads to more success.
EDIT: I guess the crappy part about this is, being close friends, it's pretty much impossible to avoid seeing her. Being in the same D&D group, which of course, meets tomorrow.