I'm going to a wedding today (leaving in about 15 minutes), so I know how you feel
It does have a sit down dinner, so I am saving most of my calories for that and maybe a piece of cake, and a glass of wine. Unless they have bacon wrapped scallops or shrimp, which are a big weakness for me (but luckily i can control it to about 2-3 of them), I don't intend to eat any of the little appetizers, which means I'm going to white-knuckle through all the tasty goodies
I ate an 80 calorie yogurt about 45 minutes ago, and I'm taking a fiber one bar for the road, since dinner probably won't be until 6ish. I wasn't going to count calories today (I'm still not going to be able to count exactly), but I'm up a pound from yesterday for no apparent reason, so I want to be extra careful about what I eat today and make sure I get on the dance floor after the aforementioned glass of wine
good luck with your party today! I know you can get through this!!!