How to get my mind off of my stomach?

OK, so I felt a twinge in my stomach, and ever since, I've been worried about puking. I can't do it because I have plans with my aunt tomorrow and to put it simply I don't wanna miss it, and I simply don't want to puke up Thanksgiving dinner. I know that it's my psychosomatic response, because for the brief few seconds my mind is off of my stomach I feel fine, but then when I worry myself I am reduced to chills and nausea. My problem is that I cannot get my mind off of it. So what can I do to keep my mind off of my stomach?