One Sunday, just over a year ago, I was windsurfing in the deep blue Caribbean. By the following Wednesday, I was in intensive care, and on the Friday in a medically induced coma which, said my doctors, I was lucky to survive.
I had almost died from malaria.
I was aware of the dangers of this disease, spread by the bites of infected mosquitoes, but I - possibly like many young adults setting off on a gap year in the next few months - didn't take the warnings seriously. As an aid worker based in Haiti since it was devastated by an earthquake in 2010, I knew about the risk. Usually, but not always, I used nets and insect repellent when working in rural areas, and I took antimalarial tablets - until they ran out. None of my colleagues bothered with medication, so why should I?
But one day in December 2012, having flown from Haiti to visit family in the Virgin Islands, I suddenly got an acute headache and a worsening fever. Even then, I wasn't particularly troubled - after all, friends who had developed malaria in Africa had been treated and recovered within a few days.
But I was unaware of two facts. First, the only strain of malaria in Haiti, falciparum malaria, can be lethal; and second, without immediate treatment, the chances of death rise exponentially.
The day after my symptoms appeared, I was due to fly back to Haiti, where I rashly assumed hospitals would be able to treat whatever I had.
But mechanical failure delayed my flight twice. This meant my spending a night in Miami and the loss of precious time. I was finally admitted to a clinic in Port-au-Prince, the Haitian capital, 48 hours after my first symptoms - by which time the falciparum parasite was hard at work. Pneumonia and jaundice caused by liver failure had already set in. Catching sight of myself in a mirror at one point, I saw my eyes were totally yellow. No wonder everything had a golden glow.
My case was too serious for the clinic's medical facilities to deal with. But thankfully, I had bought full medical and evacuation insurance - that meant I could be flown to the Dominican Republic, the closest country with a functioning medical system.
My feelings of relief as I was flown out by air ambulance were premature, though, as the intensive care unit to which I was taken was full. A friend who had come with me was handed a list of other hospitals to try: off we went on a midnight tour of the darker side of Santo Domingo, the country's capital, until we found one.
From that point, my memory is a blur. My vital organs were failing, as the parasite attacked my lungs, liver, kidney and stomach. There was fluid on my heart. As my body went into septic shock, my legs swelled to twice their normal size and my skin, eyes and urine turned orange.
Medical staff gave me numerous medications and blood transfusions and I underwent dialysis to combat the problems.
The worst part was the feeling of drowning as my lungs filled with fluid. The last thing I remember is having an oxygen mask on my face and fighting to breathe. Nearby, a doctor stared intently at a machine monitoring my vital signs; behind him was my friend, silent and in tears.
I am not going to die, I thought. I am close, but it is not yet my time. Strangely, I did not feel frightened. And then I slipped into a coma, induced so that I could be put on a ventilator that would breathe for me.
Apparently, people look pretty appalling on a ventilator. The tubes are strapped across the face to ensure they don't move. The body rises and falls in an artificially eerie way. Add this to the swelling and infection - I wasn't a pretty picture. One friend who visited was so shocked, he couldn't even approach my bedside.
I remember little of the week I spent on the ventilator. The faces of family and friends who came to visit me occasionally floated across my vision and I recall voices telling me to stay calm. There was no pain because of the heavy sedation, but I felt in a very dark place. At 33, I was fighting for my life.
At some point, though, I turned a corner. My lungs were getting better, and my liver count improved. Around the same time, I was taken off the ventilator to prevent lasting damage to my windpipe from the tubes. Doctors carried out a tracheostomy, in which a small opening is made in the neck and a tube to aid breathing inserted into the windpipe.
Slowly I emerged from the coma into the real world.
And yet intensive care is not the real world. It is an oppressive, strip-lit place of eternally beeping activity. People are dying and people are crying. There is the 24/7 chatter of the nurses. There are no windows, no daylight, no starlight. Time stops: minutes blur into hours, into days, into weeks.
Like most ICU patients, I was delirious, feeling fearful and paranoid.
The doctors needed several attempts to remove the tracheostomy tube to enable me to breathe on my own. The minute they wheeled me out of intensive care and into a quiet room of my own, I emerged from my nightmare.
In time, things returned to normal. After a few weeks, I took my first steps, my blurred vision started to clear and I began eating again. Food had never tasted better.
My mood dipped, though, when I realised I wouldn't be returning to my life in Haiti - in fact, I wouldn't be doing much of anything for months. My wonderful doctor - without whose determination I believe I would have died - noticed this and pushed my wheelchair out into the sunshine. After a month of windowless hell, that was blissful.
Weeks later, and still feeling fragile, I left hospital to stay in a nearby hotel. My condition improved steadily and, following numerous tests and surgery to close the tracheostomy, I was allowed to fly home to London. There, I had surgery to get rid of scar tissue in my trachea from the ventilation tubes. It took six months for me to feel normal.
Being very ill has taught me a lot, not least about complacency when it comes to protecting my health.
My message to would-be travellers is this: if antimalarials are recommended, take them and stock up well - they may save your life.
Try to avoid getting bitten: use spray, nets and wear long-sleeved clothing. Fever and other symptoms should be checked immediately. If going to remote areas, a malarial testing and treatment kit is useful. And always make sure you have good medical insurance.
If my terrifying experience can help save just one young life, it will have been worth it.
Mandy George is fundraising for Malaria No More UK. For details, go to justgiving.com/mandygeorge