My son is 8 weeks old. In another 8 weeks I go back to work and his nanny will start to come. By that time I want him at least napping in his crib. I try to put him in there after rocking him to sleep for a nap but he wiggles around until he wakes up even though he is swaddled. How do I help him nap in there? I feel like I ruined it by having him sleep in a rock n play.