LS, this is a topic that is very familiar to me personally so I hope my ..words (not necessarily advice) helps somewhat.
I too struggled for a long time about incorporating drinking into my diet without feeling completely guilty. For many months my routine consisted of heavy restriction when I knew I would be drinking that night. The thing I learned eventually was it was not worth the stress. When you drink, even if you drink and get drunk, you do not consume gross amounts of calories unless you are only drinking very kigh calorie cocktails and have several (such as cream based drinks, pina coladas, etc..martinis, straight liquor, even beer does NOT add up to that much). Finally, I learned to settle a balance. Because I know that if I try to be "normal" and have a regular dinner and such and just save room for drinks as "dessert" I know I'll end up being miserable because I still won't feel comfortable given my margin of error. So what I usually do is have a normal breakfast, normal lunch and then a SLIGHTLY (and i mean a difference of maybe 200 Calories- more than one drink's worth!) and then go out and have fun. Yes, realistically this means I have 2 large snacks and part of dinner's calories worth for alcohol and any munchies, which, also, is probably too much "room" in the end, but this is the amount it takes for me to be completely comfortable with drinking and snacking at night..because realistically, if Im truly honest, I wont physically be ABLE to drink enough calories to make up the difference, and if I have one or two and a few nibbles or snacks of fries or nachos, the calories still won't add up that much. Then, the next day, I feel like my day way basically like any other day and I don't feel the need to restrict or anythign because I had already made enough room for that day itself.
Hope that helps somewhat..but Lenin is on the right track as well..just make a little room on the day OF and forget about it the next day- forget completely! (Minus any morning afters that aren't so wonderful..in that case try to eat regularly but alter the food so it's stomach-able)