Formula Woes - Alimentum Excessive BMs?

Hi All -

Baby number two here is a bit more challenging than baby 1 (now 5).

After 3 days of uncontrollable, no ability to soothe, screaming/crying for about 14 hours a day, unable to lay flat, straining to poop or fart, we made the choice to move our almost 7 week old to Alimentum from 360 Total Care (both ready to feed vs powder) Friday evening. My first had CMPA and it worked great for her. Baby 2 is a lot happier, eating well, peeing, etc but now seems to have loose stool at almost every diaper change. This morning there was a bit of blood but none sense. We contacted our on call ped, they said it seems OK but will see us in office tomorrow to discuss, review diaper pics, etc.

My question is - has anyone experienced this? Her BMs were pretty normal texture on 360, and I remember my first always seemed to have runny stool for a long while. I’m guessing it could just be the formula but I don’t remember it being this frequent.I’d love to hear any experiences!