My next step is to try him on soy formula to see if it is an allergy. His symptoms definitely seem like an allergy. Vomiting, reflux, severe gas, fussiness and constipation. His doctor tried to tell me his formula is milk and soy free, but that is 100% wrong. It has partially broken down milk proteins, but that's it. Needless to say, I'm looking for a new doctor, too.
Keep praying for Tristan that we figure it out and me that I'm still sane when we do.