This girl i feel like just used me but i cant tell?

ok so i met this girl that lives a couple of miles away and out into another town.. we got to a cool start and were able to hang out like every day.. but the 2nd time we hung out i went to her somewat house that she shares with her x .. they get along ok usually but anyway the nite went well but near the end ther was drama between the 2 and i felt wierd well i was there for her to back her up after it was done and over with and i went home and stayed up and txted her.. the next time we hung out which wasnt the next day but the day after.. and it went well and we actually really connected that day well i thot i brought a jacket and let her keep it so she would have somethin u know just to remember the day by cause it just was a good day .. well the next day at work we wer talkin and we just kind started talkin as if we were dating u know but were not but it made me feel as if we were but now im feeling dumb for it cause today we were suppose to go to one of her friends house to go swimmin but her x gave her a ride there and went there and i decided not to go cause i found out b4 i left that apparently theyre gettin back together and now im feelin like **** cause i thot we had somethin but apparently not.. the thing is i also told her how i felt the nite when they had theyre big fight so i dnt know... i feel like i was used but the thing is they were x's b4 i was even in the pic so idk . i just want her to b happy tho but then again im 2 nice idk im just a dummy i think lol well could u just help mabye put some input on this to mabye help me feel better or something