Would you call this betrayal?

Today my friend and I where supposed to meet up and her college and hang out, [lets just call her Sally]. I arrived on time at campus but had an old map and got lost and got to Sally's dorm an hour later plus I forgot my phone, she wasn't there so I left and went home. I got home and told her I was sorry and she told me she wasn't even on campus but in town (I commute to another college and she dorms at hers). Slightly annoyed I took a nap. My sis (we'll call her Jenny) came home (one yr younger and goes to the high school me and Sally both went to and its across the street from the JC Sally's high school boyfriend goes to [lets just call him Tony]) and Jenny asks whether or I was supposed to be hanging out with Sally today because she saw Sally and Tony driving around by school. I feel totally betrayed, I totally got ditched for her boyfriend, should I just end our friendship? It's not like I'm not in college and don't have tons of friendship opportunities. As an outside observer what do you think?