Is it okay that my 4 month old doesn't nap?

8hours is no where near enough sleep. It's normal for a overtired baby to nap for 30 minutes then wake up. Also when they are over tired they wake with the startled sleep patteren. Try taking him for a walk bump his crib, drive in the car, anything to get him to sleep during the day!!!!!!! Over tired babies can be prone to SIDS as they become so exhausted they don't naturally move their head while they sleep. Contact you HCN for help.