Pot Luck Lunch at work today!!!

Options
There is a pot luck luncheon at work today. It's a Soup & Salad pot luck, and everything is homemade. I have been pretty dedicated to my health and nutrition and don't want this to be a stumbling block. Just looking for support!

I know that I should have a plan before I have lunch, but my mind is blank. I'm not sure how to account for homemade foods when I don't have the recipes. What do you do? Find something similar in the database and call it good?

I do not want to blow it and try to "start over"... I know that one meal won't ruin all of my progress, but in the past, a day like today has been the first step of my backslide.