why are you staying up all night with your daughter...if she has her own room and she has her own bed then why isn't she in her own room in her own bed even if she is having a hard time sleeping?
I have a 2.5 year old and she never sleeps well with someone else
All children are different but there is no need for you to keep reassuring her
perhaps your reassurance is actually NOT reassuring but rather making her feeling more and more insecure