Has anyone else had this problem?

My two month old son has started to reject his bottle after eating only two ounces. He normally eats six ounces every three or four hours, but as of three this morning, he has stopped eating after two. I'll burp him long enough to bring up a really good belch, then try to give him back his bottle. He'll sip for about five seconds, and then start wailing. When I give him his pacifier, however, he immediately quiets. Maybe he isn't feeling well? Maybe he's going through a growth spurt (but I would ume he would want to eat more)? Maybe colic? I'm open to any possible solutions other mommies can offer. Thanks!