this happens to me alot. i cant exercise because i have to go to work or because my friends (who are all super skinny and never exercise) want to go out or something. The only time I can exercise is late afternoon, so if i cant do it i write in my food journal: couldnt exercise today because i was forced to do something else. then i know that it wasnt my fault and the situation was beyond my control. its really hard not to overeat on days when you cant exercise too cause you think what the hell this day is wrecked anyway. its so hard. But just remember its not your fault and you have to overcome the injustices of the world.