In 1989 my young husband of one year died and grief had set me somehow about half an inch out of my skin. Everything looked and felt wrong wherever I was, and I had a constant feeling that if I stepped out in front of a bus and it didn't stop, I wouldn't care. I wasn't actually suicidal but I certainly wasn't paying very much attention to life. I didn't see the point in anything.
After six weeks, I ran away to Australia to spend some time with friends who lived in Cairns. On the second day I went out to the Barrier Reef to do some snorkelling.
The ship that took us out to sea was crowded and there was a clear announcement on where to swim and where not to go. 'Avoid the deep water,' said the announcer. 'You're safe in the shallows and we keep an eye out for you. No one's ever been hurt in the shallows but you must stay there because there are sharks in the deep water and we believe two divers were killed by a giant barracuda only a few weeks ago. That guy wasn't within 50 miles of here but it's best to be sure.'
Into the water we all went and I floundered around for a while, hating it. My mind wasn't relaxed enough to deal with all the shouting, giggling of the happy folk around me. What did I do? Yes, of course I swam round the boat. I had completely forgotten what the announcer said.
The barracuda was right there; lurking. It was enormous, with great black marks like portholes down its side and teeth that made me shiver. It was side on when I first saw it and about 20 metres away but it flipped in less than a second to face-on and came towards me so fast it was like a blur.
It is true that time slows down in a crisis. I remember the terror - and I also remember thinking very clearly 'I want to live.' Until that moment, I hadn't been sure.
A voice cut in to my thoughts very clearly 'Swim forwards and make as much noise as you can. When you get near, hit it on the nose. If it turns, poke its eye with your thumb.'
I did the complete opposite of what instinct wanted me to do - swim away as fast as possible - and obeyed the voice without thought. I swam straight at the barracuda, yelling under the water.
It flipped away just as I hit out at it.
I lay there and watched it; it watched me. Being a journalist - and afraid that no one would believe me - I took a photograph with my underwater camera. The voice sighed. 'You could swim backwards' it suggested.
The barracuda stayed stationary. I swam backwards; never knew I could do that. When my legs touched the side of the ship I turned and swam round it as fast as I could. Out of the water, I vomited with fear and shook like a leaf.
I didn't tell anyone on the ship; I was too scared of being told off and there was no one else who was about to be as stupid as I had been. But as I sat, wrapped in my towel, shivering, I knew I wanted to live. Henry's death was not the end of me and I would survive.
I still have the murky, slightly out-of-focus photograph of that barracuda on the desktop of my computer to look at whenever I'm feeling small or scared. It always helps.
Life Less Ordinary is a weekly blog series from The Huffington Post UK that showcases weird and wonderful life experiences. If you've got something extraordinary to share please email email@example.com with LLO in the subject line.