We recently switched formula from Similac to Enfamil Gentlease because our six week old was experiencing lots of gas and spitting up. So far, the Enfamil has proven to be a better fit for his little tummy. Here comes the TMI part... his poop has become a dark greenish color and mushy. Anyone else that uses it have this same experience? Dr. Google tells me not to be concerned but of course I am. Just wanted to see some responses before calling the pedi. My gut feeling is that it's the change in formula causing it. TIA.