still not eating well

Hannah
We are going on 3 days of my newborn (5 days old) not eating well. He sleeps a lot and doesn't wake to eat. I'm stripping him down and changing his diaper and still not really interested in his bottle. We are formula feeding. 
He's having the recommended wet and dirty diapers everyday though. 
I left a message with our doctor, but any thoughts while I wait to hear back from them?