Son long story short we changed LO's formula. She has been transitioning for about two weeks to the new formula, ending today. In the last two days, she has become constipated. Hard stools, serious grunting, but still on the same schedule. Do I wait a day and see if being totally on the new formula changes things, or do I switch her back, or just call the doctor? She doesn't seem to be in any pain and her stomach still seems soft.