my son is 2 weeks and 4 days old, and he is strictly breastfed (he poops after every feeding most times before he's even finished eating, and burps amazing) his ped prescribed enfamil vitamin d, and i've noticed that he'll get very fussy, kicking, and didn't poop after eating, he would latch for a few seconds and scream at the top of his lungs. i gave him gas drops, moved his legs, and massaged his belly, and he finally pooped, now he's back to his normal happy self. has anybody else has a similar experience with this kind of vitamin d, and any suggestions on what kind to switch him to?