I have to let her go, because I'm too crazy about her?

I work with this girl and we've been good friends for a while. We've always had great chemistry. Other people we work with say that we would make a perfect couple. She's even made jokes that we would end up getting married. A few months ago we ran into each other outside of work and hooked up spontaneously. It felt very passionate for me, but I think something was off for her. A few weeks went by at work of us acting like nothing happened and I started to fantasize more and more about her until I couldn't take it anymore. I just told her how I really liked her even though I valued her friendship, but I wanted to be more. She said she's cold when it comes to relationships even though she likes me too. I don't understand what that means, but I just said okay and we went on about our lives. We continued to flirt and come together emotionally and I have gotten to the point where I am completely obsessed with this woman. I can't stop thinking about her. I've even tried to go on dates with other women, to move on, but I couldn't get her out of my head no matter how hard I tried. Yesterday me and her were sitting down talking for about 2 hours and I felt like it was a reasonable time to ask her out. I asked her what she was doing today and she said that she was going to sleep all day, which is a typical excuse. I asked when I can see her and she said that what I got was all that I was going to get. She said she just can't see me, offering no reasoning, and seemed really nervous about it, and I said that I accept her answer. We continued to talk about a lot of other things, and eventually parted ways. Im at home now and thinking about the whole ordeal and how our of control I have gotten and I've come to the conclusion that I can't be friends with her anymore. This hurts a lot and I wish we could, because we have been best friends for a while, but I don't think that I am capable of distancing myself enough from her emotionally to be friends and maintain my own mental health

I have to let her go, because I'm too crazy about her?
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