>>33243040 (OP)This is funny because I was in the exact same situation. Female coworker had a crush on me, and frankly it was mutual, but I just didn't want to be distracted at work so I was a bit colder to her than I should have been.
It got bad to the point that one day when I went to her desk to ask her for help (I had no choice, she's the expert in the domain I was working in) she was acting exactly how a gf acts when they're mad at you. Tone of voice, body language etc - it was so obvious that I got self conscious and I was looking around to see if others picked up on it.
After that I made an effort to be nicer to her. Always saying hi to her, making an effort to talk. She slowly warmed up to me but was still also feeling some kind of way.
The thing that changed things is we had a team lunch event at some restaurant, so I made an effort to go sit next to her. We ended up excitedly talking for the whole team lunch just to each other, then we walked back together separate from everyone else just talking. From then on we were really flirty with each other, like holding deep eye contact and just smiling, ending up physically close etc..
So my lesson is to just make an effort to be nice to her. Ignore her bad behavior, just be consistently warm and nice. Unless she's got serious issues, she'll eventually warm up. Trust me, if she's attracted to you, she WANTS you guys to be good again.