Have you tried giving her a pacifier again? It would not be the end of the world. We adults have our creature comforts (coffee, chocolate, ice cream, alcohol, chewing gum, cigarettes, etc...) yet we are so quick to snatch away what comforts a child for the simple reason that they "should" outgrow it by a certain age. It sounds like she is experiencing separation anxiety. I went through very serious sleep deprivation for over 2 years, and I know it can cause insanity! For the sake of everyone in my family, we co-sleep. We have a king size bed, and our 4 year old sleeps in a twin bed right next to ours. Most nights, she climbs into our bed at some point and goes right back to sleep. I just read in Mothering magazine about a mother who let her 3 year old start nursing again. The problem was jealousy of the new baby rather than sleep disruption, but regardless, doing this improved the situation, as the older child got the comfort she desperately needed from her mother. If you are lactating, this may be worth a try. The "cry it out" technique may seem to work, but it sets up a "protest-despair" disorder and is actually potentially emotionally harmful. Young children need to know that their needs will be met, that the world is a safe, secure place. "Self-soothing" is a myth. The child actually just withdraws, gives up, and loses faith in the parents being there when she needs them. I understand your frustration, as I have been to that same sleepless hell, but I hope you can find healthier ways to deal with the issue. It will be worth it in the long run. Good luck!