My very first set, which I do have on YouTube and I may be brave enough to share one day, I was fighting a fever and a nasty sore throat. But I got through the set, got an encouraging amount of laughs, and I couldn't speak for two days straight afterwards.
I know that a lot of professionals really have to bite the bullet and there are stories abound of singers excreting all manner of bodily fluids in the name of the dollars and pounds they are being paid to perform.
What's the sickest you've ever been while performing?