You need to learn to stand your ground instead of giving into peer pressure.

Your friends owe you a drink...of Pepto-Bismol and Imodium.

That's terrible, I've always been scared to have that happen in a public restroom (for many reasons). Especially a night club bathroom...ick. I'm sure choosing which to use the toilet for, was a difficult choice. Like the earlier commenter said about withstanding peer pressure, this situation may be a really good motivator for you to trust your own judgement in the future. It's hard when you feel like you are letting others down, but real friends would have been more concerned about how you were feeling, rather than pestering you to got to a club for their own entertainment. Silver lining: the club is mostly filled with strangers, so no one really knows who you are, which might lessen the embarrassment.

Your friends are idiots for dragging you but if I felt that bad I would have flat out refused no matter what.

None of your friends felt awful enough for dragging you there, where you were clearly ill, to drive you home?

Self inflicted I'm afraid, next time listen to your body

A crowded place with loud music, drugs, and drinking, your friends thought this would be a good place to drag a sick person? Cause alcohol and dancing always help with illnesses. You do need to stand up for yourself more, if you're sick, you're sick, tell anyone who pressures you to just go away, but your friends are not only idiots, but dicks. They should have cared enough to make sure you were ok, not drag you out to the last place a sick person should be.

Hey, at least it's not your bathroom

I don't think "letting it all out at the club" is a phrase meant to be taken that literally...

Your friend is an asshole