what did i do wrong now?

So i met a girl about a year ago,just 2 days after i left a very long relationship.Me and this girl have had 2 major fights in wich she said i'm not good enough for her and after i changed we started hanging out alot,i slept at her place,she came at my place but we didn't even kiss,she told her friends i was her boyfriend but while i was with her at some of her lady friends she kept making jokes about other guys.Last 2 days she was sick and i stayed with her all the time to take care of her until she had to go home for some stuff and i gave her one of my t-shirts.When i went back at her place after a day i said if i can have the shirt back,it was a thing of moment but she said later that i'm never gonna chance just because i talked about the damn shirt and even if we had all the good time toghether just for this unintentional thing i should just drop any idea with her even if i told her that i didn't mean anything bad...i was just really tired from work and wanted to get at my place to rest.Was my asking for that shirt such a bad thing to throw away all the good time just for this?