Mommies, can you tell me about the baby's poop? ? He is 3.5 months old…

Mommies, can you tell me about the baby's poop? ? He is 3.5 months old, hasn't pooped for 5 days, he used to go twice a day before that. Today he went, and there were two small streaks of blood, has anyone encountered something like this? Pediatrician wrote down, waiting for an answer.