4 Year Old - how to entice into sleeping all night in her room!

[PickledLily]

Wasn't sure whether to post in Behaviour or Sleep, but let's try here for starters.

4yo used to go to sleep in her own room very quickly generally (5-10mins) with me sitting next to her. By midnight she would be in our bed for the rest of the night. All good so far - it's been the best way for us all to get as much sleep as possible (we tried gradual treat and other things many times, but no success).

This has all changed in the last few weeks. She'll happily have a bath (this is new, it used to be a battle), but then refuses to go to bed. Cue lots of flouncing around the bedroom. She eventually told me that she's scared of the monsters in her room (she's been having lots of night terrors) and she's frightened that I might go away and not come back (she's like this during the day too). The only way to get her to go to sleep (I'm not leaving her to scream upstairs) is to put her in our room but even then she won't settle unless she's practically wrapped around me.

She has recently given her dummy to the dummy fairy (her instigation, but unfortunately she'd changed her mind by the evening by which time the dummy fairy had already been). The lack of dummy isn't helping, but from what I see on MN, the not wanting to go to bed is a fairly common theme at this age.

Anyone else experienced this? Any suggestions for easing her separation anxiety and getting her sleeping on her own?