It would have happened even if you gave your baby gerber first and then enfamil....I have f our and had to switch formula twice...it happened both times once they got use to new formula it went away...of course check with your doctor...but this is what happens when you switch
Only worry if the babys in pain ypu can also talk to wic and have them change formula i get wic my daughts formula has been changed a good 4 times bc she spit up so much....she is on soy and poops like every other day. Doctor says its bc of the soy.
I wouldn't b concerned. formula fed baby can go up to 3days with out a bowel movement n being formula fed the farts n poos smell way worse. as for spit up try burping after each ounce n keep baby upright after feeding. Congrats on being a new mommy.