Is this bad manners, a game, or am I the one overreacting?

[O'Hare]

Today my friend came into the canteen. He was whistling really loudly when he came in. I didn't look up cause I didn't know if it was him until he was right inside. Then he started singing, bit of an act really, showy like he was in super great form and when he was singing he was doing it really loudly and making himself sound great like an x factor audition. He went talking to one or two people, then out of the blue shouted a question over to me. Then after that he was talking to others beside me but not making eye contact with me even though he was talking in my direction. Then, when he could have sat beside me, (it was the obvious choice of seat), he put his stuff next to this guy, but didn't sit there, it was like he was putting it off. I felt hurt so I left. It was like I was invisible. Why would he behave this way to me?