Should i cancel this date with this girl?

Ive been talking to this girl for about 6 months. Mostly online (i was out of state) but for the last 2 months we've been dating...or so i thought.

Im leaving soon and i told her to message me when shes free so we can hang out. The 2 days she told me were days i was busy so i asked her if those were the only days. Then she (in summary) the conversatoin goes like this

Her: Im busy. ive already sacrificed a lot of my time

Me: didnt know it was a hassle. We dont have to

Her: forget it (then 10 minutes later) im letting you know im going out of my way because you want to hang out

Me: Told her how it seemed like she was having fun which is why i sacrificed my more of my time and my money (hour drive away and i always paid)

Her: She said she wasnt sure how she felt about me because we only got together 2 times (because she was soo busy) and that she thinks im looking for a relationship and im a nice guy blah blah

Me: ok

Her: i would still like to talk to you if thats alright. and we could still go out

Me: ok. movie? (so i wouldnt have to talk to her)

Her: lets go play pool then go to a movie so we can talk

Me: ok

I figured id go just to see what happens. Then i see she post on facebook that she went to a golf park with some 40 year old dude (she's 20) today. It really made me feel like a piece of **** so i dont wanna go anymore. Should i be a "nice guy" and cancel or just not show up?