My son will be 5 weeks old tomorrow. He had is one month checkup yesterday and was looking good. I didn't really notice it too much yesterday until last night/today. When I try to feed him he gets really fussy. He'll start crying through his feeding, he won't close his mouth, he takes longer to eat. I make him 4oz he only eats 3-3.5, sometimes 4. I feed him when he's hungry and he's been going 3 1/2-4 hours usually. He went 4 1/2 hours once today. Hes not really tired when he eats, I know it's not gas cause it happens when he first starts eating and he'll only eat like an ounce and start acting that way. He's on formula and has been since he was born, he had similac infant, because I have wic and that's what they give you. Why is he doing this? What should I do about it?