Three weeks is a common fussy peak, with longer night stretches just starting.
About 14 to 17 hours per 24 hours, including naps.
Typically 4 to 6 naps a day.
Often 3 to 4 hours at a time.
Every baby is different. These are typical ranges for healthy, full-term babies, not targets. The easiest way to know your baby's normal is to track a couple of weeks and look at the pattern.
Thungu is a baby-tracking bot, not medical advice. If you're worried about feeding, weight, sleep, or development, talk to your pediatrician.