My 17 months old has always been a good sleeper, in an easy routine - these older months it was bottle around 7pm, in bed awake for 7.15-45 depending, lights off, Ewan the sheep on, and happily let us leave her and fall sleep til 5.30-6.30am.
The past 4 weeks something's just broken! 
she started refusing to sleep/crying if took her up to cot like normal so now she's started staying down with us til about 8.30pm. Even at this time she won't sleep now, we're having to rock or lay on our bed with her til she's gone and then move over and more to point she's now waking at 4am every morning:
Before I could rock and put back down, now it's like she knows each time and clings/cries for dear life unless she ends up in our bed! We had 15 months of her never spending any time in ours, help!!
I don't know what's happening!