On an otherwise perfect June afternoon during Royal Ascot this year, I had been presenting for the BBC as well as socialising with friends.
I'd had a wonderful day. I'd had a little champagne, the weather was good and I'd even managed to pick a winner in Lush Lashes!
Towards the end of the day I went back to the trainers' enclosure for a picnic with my friends. I ate a delicious prawn salad before we made our way to our car to head home to London.
As I walked I started to cough: a tickle-like cough in the back of my throat. I asked my friends if they could sense anything acrid in the air and whether anyone else was affected.
They said: 'No, but perhaps the pollen count is high.' I am not usually sensitive to pollen so it seemed strange.
My eyes began to water and I bent over as the coughing fit took hold. I wiped my eyes and was aware I must be suffering from some form of allergic reaction. I thought I should try to obtain an antihistamine tablet.
There was a pharmacy across the road, but it was closed. I started to panic then as I could feel my tongue swelling rapidly.
A policeman was standing across the street and I stumbled towards him.
My friends told me to keep calm but by this stage I knew something was seriously wrong. My throat was constricting and I began gasping for air.
I looked for somewhere to sit away from the main road and I staggered down an alleyway, a sense of impending doom descending on me. I felt as though I would drown alive.