It was handy that I collapsed almost outside the GP's surgery. Any further up the road and I would have needed help to get there.
Apart from the embarrassment, there was that clammy, shivery feeling, pins and needles, the sudden faintness and the absolute certainty that I was going down with a ridiculous urge to protect the contents of the two shopping bags I was carrying at the time.
All classic indicators of what – a heart attack? Angina? A brain tumour?
Well, as it turned out they were symptoms of my addiction. Coffee.
This sounds preposterous, but after a tetchy conversation with my doctor (Her: "Are you on any, ahem, artificial stimulants." Me: "I'm a middle-aged mother of two – you think I'm doing drugs?") and several weeks of denial after hospital tests, the sad truth was evident. Caffeine had screwed my system.
Let me go back. Coffee has always been my beverage of choice. It got me through the Leaving Cert, college exams and most work days. I would veer on my lunch break towards cafes with 'decent' coffee rather than a great sandwich. At home I drank instant – lots of it.
An American friend returning home was clearing out her house contents. I selected her coffee grinder and a love affair was born.
It coincided with me starting to work from home. Suddenly introduced to the world of real coffee, I took to it like a junkie to mainlining. I sampled the beans of the world.
My morning travels would take me to Columbia, Ecuador, Ethiopia and beyond. Sumatra was saved for weekends.
One Christmas my (tiny) kids bought me a box of 12 tins of beans from around the globe. Santa had come. By the day I collapsed, I was drinking the equivalent of 40 cups every day.
There is obviously no way I could have downed that amount itself but it's over 3,000 milligrams of caffeine, the equivalent of seven venti Starbucks.
Naturally I was in disbelief and a little annoyed the GP wasn't taking my symptoms seriously. She did ask whether I was having trouble sleeping. I've been an insomniac since I was a teenager; nothing to do with coffee.
She wondered if I felt anxious. Well, I had just left work to freelance, of course I was apprehensive; nothing to do with coffee.
The pins and needles were of concern. Yes, they started up just after breakfast most days; nothing to do with coffee. Why aren't you writing this down? What about palpitations? My heart felt like it was stopping, then racing to 'catch up'; nothing to do with coffee.
I was sent (just in case) to hospital to have a Holter Monitor fitted for 24 hours. If you haven't experienced this delight it involves eight electrodes glued to your body and a Walkman-sized machine to carry around with a notebook to record 'episodes'. You must diligently record the time your palpitations occur. Hilariously, it also provides handy hints. Were you sleeping, sitting, walking, having sex? Seriously.
It was, of course, the coffee. I was banned for three months. It was, quite simply, a terrible time. Cold turkey is far worse than symptoms of addiction.
The shivers were replaced by constant cold; the pins and needles now freezing fingers. I had monstrous headaches and nausea in the mornings. The palpitations lessened but didn't go away. It was hell.
I reckoned I had it beaten until I found myself at the checkout in Dunnes Stores with a six-pack of Coke and two bars of Green & Blacks chocolate in my trolley. I don't like either. Who had put them there? It was my caffeine-starved brain.
Caffeine is a natural product. It is good for you. Around 250mg a day (two cups) improves concentration, relieves stress and may even help you live longer.
Any more than that and you can get jittery, anxious, suffer raised adrenaline and insulin levels. It is used as an appetite suppressor, without much scientific evidence to back it up.
It's possible caffeine stimulates thermogenesis, the process of heat regulation in the body and allows food to be digested with more energy. A mild diuretic, you'll certainly experience water loss, about 1.17ml per 1mg of caffeine, making the scales appear lighter, but a more potent effect is likely to be the extra energy associated with the drug, increasing your metabolic rate by around 5pc – you may feel like walking faster or staying longer in the gym.
Caffeine is found in the beans, leaves and fruit of over 60 plants, with the cocoa bean the commonest source, and is the world's most prevalent psychoactive drug. It is estimated that 90pc of North Americans drink coffee. Caffeine increases the efficacy of pain relievers by 40pc.
There is evidence of stone-age man chewing leaves of caffeine-based plants and long before the six 'Friends' found 'Central Perk', gentlemen were supping their guilty pleasure in London coffee houses.
Insurer Lloyds of London was founded in a coffee house when Edward Lloyd opened his premises in 1688 as a place for ship-owners and merchants to meet.
However, more than four cups of coffee a day increases your risk of dying from several sources.
US researchers recently found that death rates in under 55-year-olds from all causes rose more than 50pc where they drank in excess of 28 cups a week, with a greater impact on women. The effects were not pronounced in older people.
Those drinking higher amounts of coffee were more likely to be smokers and alcohol drinkers, which have their own added effects on health.
Ten years on I have my own consumption down to a fine art. I can drink coffee, but exactly two cups and both before noon. The only thing that gets me crotchety and anxious now is a bad cup.
So, it's Costa and Butler's if I'm out; my own grinder (exactly measured) if at home.
The palps are gone. I sleep every night and my fingers are functioning normally. I suppose it was, probably, I'm reluctant to admit, the coffee after all.