DS is 4 and a half months and for the past few days and nights I've had to rock him for him to go to sleep. I've never had to do this before. He normally gets himslef off to sleep, but recently has been lying there 'growling' and getting more and more wound up until I go in a rock him to sleep in my arms. He's over 18lbs so is VERY heavy and my back is now killing me. Is this a phase due to teething (he's dribling a lot and keeps shoving his fingers in his mouth). Last night I had to resort to giving him some calpol becuase he was SO tired but just couldnt get to sleep.