K.D.
The problem is that you are picking her up and doing stuff with her in the middle of the night. She has come to expect that when she wakes she will:
- get out of her bed
- get juice or formula to drink
- get her diaper changed
- get rocked or some other way put back to sleep
She has also learned that if she wakes up again, you will give up and bring her to bed with you. You need to change the expectation in her mind.
My son went through something like this around 1 year old. And I made some of the same decisions you made. I nursed him and rocked him to sleep. If that didn't work I'd bring him to bed with me (which was not cool with my hubby). My doc and I talked about this at his 1 year appointment. Here's what I did to change his expectations.
- Step 1: no nursing at night. Instead he got a sippy cup with water. I still did all the other things, except that I repeatedly rocked him back to sleep (no coming to bed with me -- my hubby was adamant about that).
- Step 2: Give him water and coax him to lay down in his bed, while asking him to lay down (this part is important for step 4). Stay by the bed with my hand in his or on top of him until he fell back to sleep. At this stage there was no picking up. It was hard, but he could be coaxed to lay down in his crib if I got at eye level with the crib mattress and kinda thumped my hand on the mattress.
- Step 3: No water. The rest was the same as step 2.
- Step 4: Ask him to lay down in his bed from beside his bed, then gradually ask him from farther away.
It took a while (about 4 months) because I only worked on changing one expectation at a time (he was the same as your daughter -- he'd get worked up and throw up if I didn't get him calmed and back to sleep), but it did work. He was 2 1/2 by the time he really slept all the way through the night in his own bed. But that came from him understanding that Mommy didn't like to get up in the middle of the night.
Basically you need to teach your daughter that if it's still dark in her room when she wakes up that she needs to roll over and go back to sleep. And don't worry about changing her diaper unless she is poopy or you use cloth diapers. (disposables are more than capable of holding a night's worth of urine, and they keep it locked away from baby's bum -- if her current size leaks after a whole night, go up a size for nighttime or get nighttime ones)
Good luck to you.
PS: My daughter is about the same age as yours -- she still wakes 1-2 times a night but getting her back to sleep takes 2-3 minutes because I don't pick her up -- we're about step 3 on the list right now.