I soooo totally get this. I call it going into "Pac Man" mode. I just remind myself of that little PacMan eating everything in my path! I swear I'm not hungry or even emotionally upset. I just start eating, and eating, and eating. And since I know it's not good stuff I'm eating, I don't do it when others are around.
I have found that if I am religious about writing down my foods and exercise, I can at least see what the PacMan episodes do to my calorie balance. I also admit that they are going to happen, and if I can keep them to one every 2-3 weeks, I still stay on the positive side of healthy. I don't beat myself up over it. I just get right back to eating right and logging what I eat.