So, I had to switch Jack's formula because it was causing some major constipation and just overall discomfort to the point where he'd scream all the time and only want to be held. I switched him over to Enfamil's Infant formula (which is iron-fortified) and it has made a world of difference in his temperament and he's finally having BM's again. My concern is with what his diapers look like. His BM's are VERY dark and kind of loose...not really diarrhea, but similar. My mom thought it was because of the iron in the formula. I'm not familiar with this because my other two had issues with milk-based formula and I had to switch to soy (which I know is not really recommended anymore) so I've never really seen anything like this. I'm really hoping it's not anything to be concerned with because he's been SO much happier since we switched, but I figured I'd ask on here before calling pedi.