Don't worry !! Just enjoy your birthday party !! As Coach Nancy has already mentioned, Spark People isn't about deprivation. It's all about moderation and portion control. I can't imagine living a life where I wasn't allowed to eat something because I was worried I'd gain weight. that's not healthy. a glass or two of wine, some cheese, a brownie, a cupcake, slice of cake, etc.... CAN all be a part of a healthy lifestyle !! Just be mindful of the portion. Indulge, but try not to over indulge too much.
AND if you do happen to over indulge, that doesn't mean your a bad person or an unhealthy one. What to do ? Just be mindful of what you eat for the rest of the week. ONE DAY of over indulging will not ruin your healthy lifestyle !!