Screaming baby 💔

Baby has seemed fine and all of a sudden tonight he just let out this loud scream and then farted. And then it happened again:( he's pooping alot. And by alot I mean in 24 hours he has gone 8 times which he was having maybe 2 a day for the past 2 weeks. He does have a bad diaper rash as well. I don't know if I should be worried. I've never heard him scream like that