thanks again everybody. It really helps to get through the rough patches when everybody on this site is so supportive!

We had started co-sleeping, and then suddenly he slept through the night in his cot... but that's all gone out the window now

looks like we might return to co-sleeping for a while - no skin off my nose! Fed him to sleep in the big bed last night and then transferred him to the cot when I went to bed. Unfortunately he woke up, but gave him a bottle and he went back to sleep for another 3 hours. The rest of the night wasn't so hot and eventually he came into bed with me at 5am. It's silly, but I guess I'm resisting the obvious solution because of the memory of that one week of him sleeping solidly all night in his cot and each night hoping that tonight will be the night he does it again

I think I will buy the wonder weeks book. Sounds like that might be really helpful.