My son will not sleep unless someone is holding him. and if I try and lay him on his back he stretches and wakes himself up. I usually have to put him in his rocker but I really hate doing thats. he's only 2 months old. I'm gonna try and have him start sleeping in his pack and play, and let him cry a little. any advise?? i heard sleeping with his sheets for a few nights so it's smells like me?