Take a deep breath, in through the nose, out through the mouth. Why should you be so upset about "eating with people you don't know"? What happened the first time you met them that has you petrified to meet them again, this time in a probably less formal setting (i'm guessing).
People are people, we all eat the same. Food in mouth, crew, and swallow. It's not all that difficult unless your shyness involves eating in front of people.
If you spill something on yourself, you are human. Make fun of it, and go on from there. Can you fill me in a little more?