Girls: What should I do about this girl (please answer, I need advice)?

I've been friends with this girl for years and I'm very attracted to her. We get along really well and have great chemistry. I few months ago I finally got the guts to ask her out but right before I had a chance to do it she told me she was seeing someone new. So I chickened out and didn't ask her out. Fast forward 4 months. We went out to celebrate her birthday, it was me, her, and a couple of her friends (her bf was nowhere to be found). At first we went to a bar where me and her talked all the time, we were pretty much inseparable. Then we went to a club and dance with each other all night (she interlinked her fingers with mine for some reason). Anyway we both must of got turned on because soon we were grinding up each other, she even grabbed my crotch a couple of times. So she eventually got kicked out of the club (when I went to the washroom 2 guys were pouring booze down her throat), and I took her home. Nothing happened, I just brought her home and then went home (she didn't let me stay the night at her house). The next day she called me when she woke up but I could tell she was feeling well so I told her to call me back when she's better. So later that night when I was sleeping she calls me because she wanted to talk, but I was trying to sleep so I told her I'd call her the next day. So the next day I tried to call her, but no answer. That was almost 3 weeks ago, in that time I tried to call her a couple of times but she's never called back. I feel pretty crappy, I'm afraid about what's going on, she's an important part of my life. What should I do?