Weve gone backwards
Sleep development will go backwards, but then get back on track again, several times in the coming couple of years. You have to not let these backward steps stress you and just go with it, knowing that when this issue passes you can get back to normal (until the next issue).
Things that will cause sleep to go crappy:
- heat
- illness
- teething
- seasonal changes (like light mornings)
- motor skill development (learning to pull to standing is the worse!)
- behavioural issues
- emotional development (anxiety, scared of the dark, fear of being alone...)
There's loads. I could go on. The bottom line is yo change your mindset from "sleep has gone crap and now it will always be crap", to something like "sleep has gone crap, as expected due to XYZ, what shall I do to get back on track?"
But then it got hot and she also learned she could sit up
Yeah, this is a git of a phase to go though. FYI leaning to pull to standing will be very similar to this stage, but worse (sorry!)
How to deal with it? It's behavioural. It might even be the very first behavioural issue you've ever had to deal with. Basically it comes down to teaching baby that while you can (as in is physically able to) sit up, the cot at sleep time is not the time or place to do this.
Its unwelcome behaviour, so you treat it as you would other unwelcome behaviour. Firm behaviour expectations and rigid boundaries. Your expectations should be:
As simple as that. This is what you expect baby to do and you don't accept anything else. So basically just keep on repeatedly lying baby back down. Over and over and over and over again. Stay calm, compassionate and caring in this. Don't get angry or frustrated - baby is going through a process of learning and won't get it at first.
A firm hand on baby's chest back while lying down helps reaffirm your expectation to lie down while also offering physical contact for reassurance.