Any advice for the sleep-deprived mama?

Sacha slept well in his cradle for the first two weeks of his life.  He woke up for feedings twice a night, and returned promptly to sleep afterward and made cute baby sleep noises from his cradle.  He then, however, discovered the delicate art of grunting and squirming, and has not been able to sleep in his cradle ever since.

I say “not sleep” in this sense:  the minute his back touches the mattress of the cradle, even if he was in a deep sleep in Mommy or Daddy’s arms, he immediately starts grunting, squirming, spitting up, etc.  He sleeps through all this, but his maximum sleep length is about 1 hour. Sleeping in Mommy or Daddy’s arms he gets a good 2 or 3 hours (if not more), just as he used to in the beginning when he used to love the cradle.

So what happened?  The only thing I can think of is that we stopped swaddling him for sleeping at about the same time he stopped liking the cradle.  However, I do not know if the swaddling stopped before or after the sleep changes. The swaddling changed because Sacha got so squirmy that he unwrapped himself in his sleep.  The grunting is a whole other story.

Now, in order for us and Sacha to get some decent sleep, we take shifts sleeping with him.  I (or Tony) will prop myself on the couch surrounded by cushions and have Sacha sleep in my arms or on my chest.  This way, he sleeps the way he did before, without the grunting and squirming.  He will then wake himself up and request a change of diaper and a feeding, then go back to sleep.  Then Tony and I switch, so that we both get some stretch-out-on-the-bed sleeping time.

Does anyone have any sleeping advice or similar situations? I don’t mind sleeping with Sacha, but I fear that he will not be able to put himself to sleep, nor be able to sleep in his crib on his own.  Or will he just outgrow this grunting/squirming thing?