Social events stress me, out, too! I find that, for one thing, if I STAY AWAY from the food area and also MOVE AROUND to talk to different people, that keeps me away from the calorie danger zone!
Before each event I make sure that I have something substantial at my home like a grilled chicken breast and some veggies, or a bowl of high-fiber cereal, or an apple with some peanut butter. I was full enough BEFORE I got to the party, so I didn't need to eat once I got there!
This past Christmas I managed to go to FOUR PARTIES and had just ice water at ALL FOUR of them! For all my life I had believed that I would somehow hurt the hostess's feelings if I didn't eat and eat and eat. At the first party I was successful NOT eating because I just spent my time TALKING and enjoying the people there. For the second party I joined a group that was headed downstairs to play pool, air hockey and ping pong. I LOVE those things, so I spent the night having fun with others, playing games I love, and drinking LOTS of water! The third party was more challenging but doable because I helped serve everyone. Nobody noticed that I hadn't eaten, or they thought I had eaten on the run! The fourth party had so many DRINKERS that nobody had a clue WHAT I was doing!!!
I also rationalized to myself that EACH of these parties STARTED after 7:30PM, and I try not to eat much if anything after that.
If all else fails just tell the people that you have already eaten your calories for the day. Anyone who causes you a hassle about that isn't your friend anyway, so don't let it bother you!
I LOVE FOOD, so if I can make this work, ANYONE can!