Good friend? or moving on?

Me and my bestfriend Katie have been friends since we were in Primary school. Very close friends. A few years ago I introduced her to my new then step moms family. My family ended up doing very nasty things to me... unforgiving things. On Katies birthday she said I would invite you out but I know you wouldn't want to so, I was alittle offended by that. Next thing I know she is up to my step moms house partying with them. Do you think this is wrong? It kind of makes me wonder if she is actually my friend. She just got back from a vacation like 7 days ago, and se still has not contacted me.