I had a funny turn about 5 years ago. I had a severe headache which was followed by left-sided weakness of my face, and some weakness of my left arm.
My GP said this was a TIA, which is a some temporary loss of blood supply to the brain.
In a nutshell, the DVLA got wind of this and suspended my driver's licence. My business was always in sales, which required me to be on the road a lot of the time.