How much sleep in a 24 hour period?

Ma

What is your babies age in weeks and how much sleep are they usually getting in a 24 hour period?

My son is 15.5 weeks and lately only gets 12 hours if we are lucky. (9.5 at night and about 2 hours during the day on a good day). He screams for several hours a day and I’m convinced he isn’t getting enough but his pediatrician said that was enough sleep and provided zero solutions.