I used to feed my 4 month old Similac Sensitive. I found a generic brand from Sam's Club with the same ingredients, and after talking to my pediatrician switched my baby to the generic brand. He actually does better on it, not as much gas and just overall a more pleasant baby. Well I ran out of the generic brand, and you can only order it online, so I have an order coming to me tomorrow but I ran out of formula today. So I had some of the small pre made Similac Sensitive bottles in the house. We use them if we need to when we go out. I have fed my baby the Similac most of today, and he was spitting up a lot earlier today, and just an hour ago at his bed time feeding, he vomited more than I have ever seen before. It was A LOT and it was clumpy and it shot across the room. Poor guy. He seems OK, but I'm thinking the vomiting has to do with giving him the Similac all day when he is not used to that. Does anyone agree or disagree? Should I call my doctor in the AM?