Going back down

Yesterday I was down to 133, today I was 132.2. Not through any good behavior on my part--I haven't made it to the gym once this week (and am not likely to with the deadlines I have), and yesterday I ate way too much all day (work retreat = lots of breakfast food, restaurant lunch, and pretty much just sitting around all day, followed by eating leftover pasta with pesto sauce for dinner. There was too much food for one serving of the leftovers, but not enough for two servings, so of course I just ate all of it rather than saving some for later!). So I have no idea why my weight is dropping when it went UP so much last week and over the weekend when I was way more active!