What is your excuse for stomachache in important appointment?

Lets imagine that you have an appointment/date with someone,you attend as promised,but after a few minutes you feel that your stomach feels unusual and you need to,youknow,do it. You also left your meds at home so that is not an option for you.

Now you can only make an excuse,could be a lie or something like that but you have to make sure that it won’t embarrass yourself or make other people feel that you don’t like to meet them. What you’re going to say in this kind of situation?