I am having a problem with my 3 month old that has been going on for a week. He seems to only want to eat for a few minutes and then he's had enough and pulls away. He whines while he is sucking and he is more comfort sucking than anything else. I'm worried he isn't getting enough. Diaper output has been okay, but is less so far today than usual.
He seems as though he isn't even hungry, yet when he pulls off, he instantly puts his fist into his mouth.
What could this be?