Ds is a very happy baby, but in no kind of routine at all. Well vaguely - he sleeps till about 11am, wakes for an hour(has a feed in that time), sleeps for another hour, then after that anything can happen. Generally he will go to sleep around midnight/1am, have a feed during the night at some point, but go back to sleep.
This last week he has taken to sleeping from somewhere between 6pm and 9pm, which is fine, but when he wakes for his late night feed, he won't go back to sleep. He is tired (overtired, possibly?), fed, warm, dry - but fights it continually. If I put him back in his cot he works himself into a yell, and the last two nights I have ended up bringing him downstairs until he calms down. Night before last - that was 2.30am, last night, 3am!!! Consequently, both he and I are exhausted, at the moment he is still asleep! (he woke for a feed at 9am but went back to sleep).
I am reluctant to put him into a "routine" but obviously this can't continue - can you give me some ideas of how to break this cycle?