Nap time help!

Help!!! Nap time is starting to consume our lives!!! My 4 month old will not nap alone.  I've tried everything!!! I see his tired cues and he will fall right asleep for me but as soon as I set him down he's wide awake, pick him up and rock and he goes right back to sleep, set him down and wide awake.  This will go on and on until he's so overly tired he has a massive meltdown and it takes me forever to calm him down and then I just rock him until he wakes.  I've tried it all... Dark room, white noise; boppy, cosleeper, rock n play, crib, my bed, etc.  I'm starting to lose my mind!!!