I was recently hospitalized for surgery and have been pumping and dumping. After blowing through my freezer stash we had to start LO on formula. He was taking 4 ounce breastmilk bottles so that is what he is getting in formula (Nutramigen because of milk intolerance). Now he seems to want to eat every 1-1.5 hours, instead of every 2-3. Does the formula not fill them up as long? Should we increase the bottle size? If so, by how much? Thanks!