Waking to eat.?

I have always struggled with my weight. I recently have been waking up around 3am, starving and it's as if I'm almost sleep walking. During the day I tell myself I will not eat in the middle of the night, as I know it's a bad habit, but for some reason or another, I always do it. I feel so guilty ALL day, everday and do not end up eating again until dinner time. At dinner time I usually eat very little because of this. I'll have a slim fast or something under 200 calories to make up for the nightly binge. What is wrong with me? It's as if I am not thinking rationally in the middle of the night, but I know what I'm doing is causing me to gain weight, the one thing that scares me more than anything.