My 2 months old grandson has been drinking formula. But the doctor changed his formula about a month ago because it was giving him lots of gas and vomiting. He initially did well on the new formula, but was bringing it up again. Now he doesn't want to eat, but is not losing any weight. He is very fussy and stays up all day, taking 5 to 10 minutes naps, but fortunately sleep all night. The doctor recons that it is Ok. Can you give us some kind of advice what might be wrong?