I remember doing my GCSEs, for one of them I was called in, in alphabetical order sat down and was dying for the toilet, couldnt go anywhere until the exam started, lucky for me i was at the end of the alphabet so didnt have to wait too long! I put that down to nerves. I put alot of things down to nerves and so do quite a few other people i know!

Coughing you maybe anxious, and rummbling in your tummy may be due to nerves also.