Girls, hello everyone! We're 3 months old, can you tell me if I'm thi…

Girls, hello everyone! We're 3 months old, can you tell me if I'm thinking right, we seem like there's a development leap: all day long he was energetic, talked a lot, slept for 40 minutes and then at 2 hours, in the evening he gets fussy and cries without reason, now he's been hanging on my chest for an hour, and hasn't slept for 3 hours. Is this a leap? How do I get him to sleep, he doesn't sleep on my chest, maybe he can fall asleep but wakes up quickly, now he's crying loudly, you could say he screams sometimes.