We started out 2 days ago with enfamil newborn and he's been super fussy, needing to poop, waking up crying, only pooping once a day, and all together not feeling well. His nurse said to switch to Enfamil gentle ease. He had 2 ozs ratifier today. Still acting like he don't feel good. Should I keep him on it? How long till he adjusts if he does. We're transitioning from BF to formula by the way. And he's 3 weeks old