need advice on Bipolar girl

I have a co-worker whom I've become friends with and over a period of time I've picked up on signs that she's interested in me.  I eventually asked her if she'd like to get together sometime away from work and she said yes and gave me her number.  I tried a few times to call but she wouldn't answer or return my messages.  I was about to just forget it when one day she came to work acting strange, very different from what I'd seen from her.  I was curious about what was going on with her so later that day I decided to call one more time.  She answered and we agreed to meet to talk.  During our date she told me she was bipolar and that's why she was acting different at work.  She was having some kind of an episode because she forgot to take her pill.  I didn't really know what bipolar was.  Anyways, we had an awesome time that day.  Talking, flirting, hugging.  We laid in bed together, just undies, and massaged each other, kissed and just enjoyed being close.  At the end she said how great it felt to be with me and that we'll definitely get together again soon.  I was ecstatic. Then the very next time I saw her, she acted like nothing ever happened.  I asked her out again, and while she said she was interested and to call her, she wouldn't answer the phone.  A few days later while at work I asked her if she still thought our date was something special and she said yes.  I suggested we do it again like we'd talked about and she agreed.  So again, I said I'd call her to set it up.  Again no answer, no return phone call.  When I talk to her about getting together she says and acts like she want's too but then ignores my attempts to make it happen.  Why not just tell me she's not interested I'm thinking?  Now, cut to a week after our date and she won't even make eye contact with me at work.  Avoids being around me and I think she's told other co-workers that I'm bothering her because of how people are acting around me now.  What is going on with this girl?  We went from friends to nothing in a matter of days and it's the last thing I saw coming.  What did I do?  How do I at least get back to where we were before our date.  She surprised me with a text message recently.  It wasn't anything big, just a simple comment, but something I wasn't expecting after all of this, after never returning my calls and avoiding me completely.   Why text me if I'm bothering her so much?  I've been reading through other posts about Bipolar behavior and I'm wondering if she was in a manic state on the day we were together.  I really like her and want to understand how to handle what's going on with her.  I want to have another date like the first one. What do I do?