6 month nursing strike

I think my son is going on a nursing strike. The past couple of days he has nursed about half the total time he normally does; some sessions are only 2 minutes long. He still has been nursing well at his bedtime feed and overnight. However, tonight he flat out refused to nurse. He went to bed without eating anything. I'm hoping that maybe he was just overtired. Has anyone else's little one done something similar? How did it turn out?

**UPDATE** Our usual overnight feeding routine is feed, diaper, feed (other breast). He fed normal the first time, but after diapering (when he was more awake), he refused. This morning he showed no interest at all. I was able to get him to take 2 oz from a bottle, but he normally takes 4 oz when bottle fed.