My daughter normally goes down for the night around 7.30pm. After that she sleeps soundly (with a feed at 10pm) until 3-4am, where she'll grizzle a few times but go back to sleep without needing to be taken out of the cot. Then she'll wake up fully between 6am and 7am.
A few nights ago this changed. She will still go to sleep relatively easily, but will wake up every few hours, including before her 10pm feed, crying like a wounded polar bear. Our usual soothing techniques don't seem to work, and sometimes she cries herself fully awake.
Around 4am we snap and take her into our bed to see if that soothes her more, but last night she just lay in bed babbling and playing. It took 90 minutes to get her back to sleep and she still woke up around 6.30am.
What could cause this behaviour? I'd suspect teething but then why was she so seemingly happy when she woke up at 4am? Shouldn't she be either tired or still crying from the teething? Why does she behave like this at night but be relatively happy during the day? What can we do to help her sleep more?
Update:
She's now 9mo, and this behaviour has recently got a lot worse. We started using controlled crying to great success, and she now goes down to sleep at 7.30pm with great ease. However the middle-of-the-night crying is still occuring, except now with more force than ever. She screams extremely loudly and violently, but I'm pretty sure she's not in pain. She has been doing this for almost two weeks and still doesn't have any teeth, so it's probably not teething, and she still does the tell-tale pause in crying that signals she's just looking for our attention.
Comforting her in the cot does not work, she doesn't stop crying and she rejects her dummy. Picking her up does stop her crying. Taking her into our bed stops her crying, but she doesn't go to sleep, instead play-fighting or crawling around the bed, which keeps us awake as much as the screaming.
We have been trying to do controlled crying in the same manner as we did for her bedtime, but it's harder because we can't stop her crying while leaving her in the cot. The longest we've left it is two hours of solid crying, but then our tiredness and guilt about the neighbours makes us give in.
Any more help/support appreciated.