My DD is almost 6 and the same as your DD. she has been the same since she was a baby ie. a shocker to get to sleep but thanks goodness, once she is asleep nothing wakes her. At 3 she would cry if one of us was not with her. When she was 4 she got better but sometimes she was really bad and I went into a meltdown many nights, because the same as you, could not get anything done until she went to sleep. many nights I would go in and lie down with her for a few minutes and I would fall asleep before her! Even now she is almost 6, she does not cry for us to be with her but will still lie there for 90 minutes without sleeping.