Why won't she date me?

Girl I've known for 5 months. She has contacted me alot throughout and at one time called me everyday for 2 months. We get on REALLY well and work together and we also had a few dates and kissed eachother back then but not now.

Sometimes she will lecture me like she is my girlfriend and flirts with me(allows me to put my hands allover her butt) and it appears that there is some kind of feeling there(tears in her eyes when we had a argument) but she has so much pride she won't admit it. We had a few minor arguments recently and it felt like we were a couple.

A few weeks ago things were going really well, she was txting me all these kisses and told me "u don't know all the things I will do to you" and how she wanted to kiss my sexy lips. Problem is at work she wants others to feel she doesn't know me, when they ask about us she says nothing is going on. She told me this while acknowleding something between us and saying "if they know they won't put us together"

She knows we click but says she was in a 5 years relationshiop before she met me and doesn't feel like she has got over that yet, the thing is...she dates other guys and tells me she even goes over to their house which obviously makes me feel not important. She told me a few guys she gets on with want her to be their girlfriend but she just doesn't have the "time"

Everytime I suggest we do something she never looks interested or makes an excuse. Yet when we are together at work, her eyes look so interested and she seems into me. She pulled my arm at work and had this sexual look in her eyes and told me she had something to tell me, time ran out as boss was nearby and when I asked her the next day she said "it doesn't matter" with a twinkle in her eye.

To me it feels like she has feelings for me but just won't tell me. I wish I knew why she doesn't want to meet me outside of work. We met with her friends a few weeks ago but we were not alone so it wasn't the same plus she didn't talk to me much. What's going on?