I'm just wondering, what do you think?

The person he was talking to probably asked who he was yelling at when you didnt turn around and thats why he said what he did. They probably laughed because it sounds like he made a bit of a scene yelling bye to you before you left. Your just over reacting man, quit being so shy and start not giving a **** what anyone thinks. Youll get 10x more friends that way anyways.