This may sound unrelated, but I was doing the same thing too and it turned out that I had sleep apnea.

After getting my bi-pap machine, believe it or not I now sleep through the night...........crazy isn't it. My dr said that waking many times at night and going to the bathroom is a fairly common symptom of sleep apnea.

Do you snore? It might be something to look into, although the tests for sleep apnea are expensive.

Take care and keep us posted.