She used to be great but has lost the ability to get herself to sleep unless she is totally shattered. I am obliged to leave her to it a bit - it's not really controlled crying it's just that ds is 3 and needs to go to bed too. It lasts for ages and I pop in often but she gets very upset and goes to sleep with that juddery thing you get when you've cried lots.
I hate leaving her to cry herself to sleep but if I stay with her she wakes and cries as soon as I leave the room so it's totally counterproductive and goes on for sometimes 2 hours, which is impossible for us.
If I put ds to bed first he refuses to sleep. If I put dd to bed first she cries and is miserable all through ds's bedtime. help!
I'm afraid I don't have any constructive advice, but I just wanted to tell you that my DD is now 20mo. She went through a phase of not going to sleep on her own at about the same time. (Although she didn't make quite as much fuss as your DD seems to be doing) She cried a lot and wanted me to be in the room with her until she slept, something that I wasn't able/prepared to do either.
Then, suddenly, about two weeks ago, she suddenly regained her old habit of waving me goodnight and going to sleep by herself quietly and with a smile on her face.
I have no idea what caused the phase to either start or finish, but I am delighted that it finally has. I really hope that your DD is the same and will grow out of it soon.
By the way, have you tried playing soothing music in her room or anything like that?