Kind of urgent!

So I'm currently at a birthday party for my aunt and theres so many people here.
There's food available and I've been eating a little trying to keep myself calm, but my stomach just feels sick now. This happens a lot when I get anxious and I end up with my digestion getting messed up. (feeling nauseous, getting diarrhea, gagging etc.) I'm not eating now because I'm worried I'll get sick,

But if anyone knows some quick remedies for nervous stomach it would be greatly appreciated! I don't want to spend my night sitting in the bathroom. If I still feel icky in another few minutes I may just leave. But if you guys could give me suggestions it would be greatly GREATLY appreciated!!