I think this is a learning experience. Sometimes we are going to overeat but we have to learn to immediately compensate for those excess calories. I remember my sister, who is a skinny minny, refusing a piece of cake once at my house because she was 'cutting back a bit'. I was gobsmacked as she is very slim but then she told me she'd put on 4lbs!!!!! I could have killed her but she honestly has the right attitude. She was aiming to lose 1/2lb for 8 weeks to get back to her ideal weight. What you're doing is probably what lots of skinny people do automatically, compensate for a blow out by cutting back, either beforehand if it's planned or afterwards if it was spontaneous. You've had a spontaneous blow-out so you need to make some adjustments over the next few days to bring your calories in line for the week and that's exactly what you're doing. It's one of the things we'll all have to learn in order to manage our weight in the future. Well done.