Why would he do this?

Ok, so I have been seeing this guy for a lil over a year. And we get along well in almost every area. We don't have any big disagreements and so far every thing we have fought about has been resolved within a short time. Th longest we went without speaking was 5 days.

So, over the last two weeks he seems to be getting more and more distant. And today he would sort of talk to me but it seemed like he was avoiding me. Sometimes he is too busy or whatever and I totally get that, but today was different, like he really either did not want to talk to me or he was actually trying to make me mad. I dealt with it all day and kinda just shrugged it off because I know he has had a pretty rough week. (we work at the same place). But normally he will say good bye to me or talk a little before he goes home and today he didn't. At all. It seems like he is trying to start a fight. Why would he do this? I don't get mad at him very often and I try to be understanding and give him space and all that, but this was out of the ordinary rude and hurtful.

Why would he start this and what should I do? should I just quit talking to him or tell him off? I really feel like going off on him about it, but I really don't like doing that. What are your mature thoughts?