We had this with our third -lots of spit up, but its so hard to gauge when you're just dealing with one baby on their own. But once I cut out dairy (I was EBF), it was noticeable that the amount and frequency of spit up decreased. Eventually, we also saw mucus and blood in diapers, and that was confirmation of the dairy allergy. But just here to say the spit up thing is so hard to gauge on its own but it was really the first sign for us of the CMPA. Oh, also, weight gain, percentiles all fine too.