Someone said that the hardest month after a baby's birth is the month …

Someone said that the hardest month after a baby's birth is the month of their birth. Well, not exactly. We were calm before the month. Now it started hell ??. He eats on hands, falls asleep. Only when we put him in crib, five minutes later he cries and screams. Before he pooped once a day. Now he can't poop for two days. Since yesterday she sleeps for 15-30 minutes every four hours, the rest of the time either cries or has tantrums, I entertain her so she gets tired. But whatever. She seems like someone swapped her. Relatives say put him in the crib, he will cry for 5-10 minutes and stop.