One thing that I can think of: is it daylight when he takes a nap? Maybe try leaving a small lamp or night light on till he goes to sleep. Maybe that is why he is having a hard time at night. My son is a very good sleeper, but sometimes he doesn't want to go to bed so I'll leave his light on or the hall way light on till he falls to sleep. He will play in his crib for a while then goes right to sleep. Or maybe try some music. That worked for my oldest son. They make lots of great and cheap cd's for babies. I hope that helps.