I had a high calorie day last week, and the next day saw a loss. Maybe a high calorie day every once in a while kicks your metabolism up a little.
Either way, I wouldn't worry about it. It was a special occasion, and in my mind those are fine... as long as you're able to get right back on plan the next day, and I'm sure you'll have no problem doing that.
Hope you and your boyfriend had a great time celebrating his birthday!