help with potential work relationship

Hi All,

this might be a long post so bear with me

I have this girl who joined our company a year ago, she is really my type and i liked her instantly. However i was in a relationship so i decided not to pursue her. Now i since my relationship ended, we started to talk and got to know each other a bit. This was back in December, after talking for a week i asked her out for a date and if she wanted to meet on new year's eve - i realise it might have been a bit too soon but i did it anyways In the end she went with her sister and 2 days later when i asked her out for a date she declined claiming that we shouldnt be doing it as we are colleagues....
After that i tried to lay off her and leave her alone but whenever i did it she kept striking up conversations and we kept speaking - every once in a while, like every week i got to a point when the whole situation just frustrates me i got more and more flirty to get something out of her but whenever i do that she either ignores my compliments and doesnt say anyting or just switches topic. This has been going on for a few weeks now - me ditching her for 1-2 days then her "coming" after me and whenever that happens i get more involved with her but then she just ditches (swaps topic or doesnt answer) when i get flirty - back and forth back and forth.... its getting annoying. This week i confronted her about what she is doing and she admitted that i am right and claimed that there is nothing wrong with me - its her.(she doesnt have a boyfriend - so it must be some other issue, and she didnt say that it is because we are colleagues as said previously) I thought we gotten to a breakpoint by this conflict where its all or nothing but the next day she strikes up the conversation as if nothing happened.... I really really like her but at this point it is just frustrating and i am going a bit crazy and not sure what to do...not even sure if she likes me or just playing around...

Any advice would be highly appreciated!!

Thanks to all who post :9