5.5 month old needs to be held at night

Nicole
We put him in his crib at 2 months. He's never slept great but around Christmas he was sleeping 3 hours straight, sometimes 4. Then the time got smaller to up every 40 minutes and then it got to the point where I couldnt put him down at all. I breast feed and nurse him back to sleep. I refuse to do cry it out. Any suggestions? Is this just a phase, possibly part of leap 5?