My son is 19 months and for the last 7 months has done great sleeping. Gets bath, drinks milk and falls asleep in his own crib. Last 4 days he will not sleep but screams at the top of his lungs, crying. We tried letting him cry it out, after 45 min couldnt take it anymore, picked him up and rocked him to sleep. If I try putting him down before he is asleep, he crawls on me and hold me at a death grip. We do not know what to do, but do not want to go to the days of rocking him to sleep. Please help!