My baby is 7 weeks and is formula fed, he takes about 6oz every 3-4 hours and every morning he wakes up straining and uncomfortable and I keep checking his diaper for poop but nothing? He eventually does a HUGE poop that fills about 2 diapers! but it isn’t hard it is pretty normal looking just huge! And once he’s been he is like a different baby and so much happier! Is this something he will grow out of?