Appendicitis is the worst pain I've ever experienced. The three-ish hours from when the pain first started to when I got in the ambulance were horrific!
I was vomiting near constantly, to the point where I'd thrown up my stomach lining. I had complete tunnel vision, everything was black except the very centre of my field of view. I felt feverish, I sweat all over. Not to mention the physical pain. It was torture I wouldn't even wish on my worst enemy.
When the IV painkillers finally took effect, it was a relief I'd never known before. If I remember correctly I actually fell asleep for a bit, likely due to exhaustion from earlier.
I later learnt it'd gone septic too - scary stuf - but luckily some strong antibiotics and a surgery later, I was much better off. That experience only served to renew my appreciation for the NHS fir sure.
Onii-Chan