Not sure wat to do any advice would be great especially girls?

i understand that most girls flirt with there guy friends...but me and this girl the flirtation was more umm intense...and it seemed like u knw we were gonna start dating..then suddenly at a party she tells me she has recently started talking to this guy she used to like...but wasnt sure about him cuz he is a jerk to ppl , but not her...wow that kinda hurt the rest of the party i tried not to let it phase me she tried dancing with me i did, but then started to pull away lucky for me i hit it off with a friend of hers and we hung out all night...im kinda in the middle i just feel like walking away or fighting for her...but i feel played u knw...not sure wat to do...and she is always texting me i respond...but i dont knw im just really confused any advice would help