My lo is 7 weeks old. Since we brought him home, he slept either in a swing or a rock n play at night. We are trying to transition him to the pack n play / crib before I go back to work and he goes to daycare. He doesn't seem to like sleeping flat on his back. He will be sound asleep when I put him down and 10 minutes later, he is just full of noises.  Any suggestions on how to make this transition a bit easier?