Baby different after shots?

My baby had his 6 month shots yesterday morning. That afternoon he was a little fussy but he took a nap and seemed better and back to normal. Last night though he was up every 45 minutes and I gave him Tylenol and he went to sleep for a couple hours straight, woke up happy and seemed normal. But now he is refusing to eat. He doesn't seem hungry either but it's almost 12 pm and he has only taken 3 ounces since last night around 6 pm.

Could this be from the shots? He isn't acting very hungry either and gets upset everytime I try to feed him. He has always been a great eater!