E.A.
First, let me say that I'm sorry! We lived with a challenging sleeper for several years and I know what a toll it takes on you! (We still have occasional problems with our now 4 year old.)
Here is something that finally worked for us....I drew a picture of my daughter in her bed sleeping. You could take a picture of her posing in bed asleep, too. I attached the picture to another sheet of paper that had the nighttime expectations on it. Our's says, "Did I sleep all night?" and "Did I stay in my bed all night?"
I went to the local dollar store and bought enough little toys to fill a shoe box and I decorated the shoe box with ribbons and wrapping paper.
Next, I introduced the concept to my daughter. We discussed the picture and the questions. I showed her the "treasure box" and explained that, if she was able to "sleep all night" and "stay in her bed all night" (except for trips to the bathroom) she could pick something from the box in the morning.
We role-played where she was the mother and I laid in her bed and did the "wrong" things while "sleeping". I asked her if that would get me a treasure box treat? She laughed and said that it wouldn't. I then modeled the correct behavior for her so she could see what I wanted. I even modeled asking her to help me go to the bathroom and going right back to sleep in her bed so she would know that was OK to do.
Every night before bed we reviewed the questions and I mentioned the treasure box waiting for her in the morning. It worked for us! Within two nights we were sleeping soundly! We still have some periodic issues, but the treasure box isn't used any more on a regular basis. We were able to fade it out little by little and I can bring it back if we have a bad couple of nights in a row.
Yes, $1.00 a day is an expensive way to break your child of the middle of the night waking, but what would you be willing to pay for a good night's sleep?! I would have paid much more than $1.00 a day! Ha! Ha!
Sorry this was so long, but I wanted to explain the process in detail. Good luck! I hope you can find a solution soon.....you all need your rest!