The pain tore through my abdomen like a bolt of lightning. Ouch!
Clutching my side, I waited for it to subside.
I had been feeling rather queasy and light-headed all day, and I was finding it hard to stay focused as I served drinks at the hotel where I worked as a bartender.
'Must be coming down with a virus,' I sighed, clutching the benchtop to steady myself as I was racked with pain again.
'Are you okay?' my boyfriend, James, 23, asked.
We'd met when I'd left my home town of Brisbane in 2012 to head to the UK to travel for a while.
Both working at the same hotel in the picturesque Lake District, romance had quickly blossomed.
Now we lived in a little room above the premises too. Usually I loved my job, but today these strange pains were making it unbearable.
'I think I'd better go for a lie down,' I told James.
Heading upstairs, I lay on the bed and tried to relax.
But soon, a dull ache was spreading through my back and up my right side.
I ran a bath, which helped a bit, but when James came to check on me an hour later, I was curled into a ball feeling terrible.
'I'm calling a doctor,' James said firmly. He contacted our local GP, but no-one could see me until the next day.
I popped a paracetamol, but within half an hour I was in so much pain I couldn't bear it any more.
James had to stay and mind the bar, so we called for an ambulance to rush me to hospital.
And as I told the paramedics my symptoms, one of them had a question.
'Is there any chance you might be pregnant?'
I thought for a moment. Was it possible? I really didn't think so.
I had been on the pill for years and I couldn't recall missing a day.
Although my period had been a little irregular, that wasn't unusual for me so I hadn't given it much thought.
Besides, my 70-kilo frame hadn't really changed much lately. My belly wasn't round or large, my boobs hadn't grown or become sore, and I certainly hadn't had any nausea. Sure, I may have put on a few kilos, but that was just holiday weight.
'No,' I replied. 'I think it might be appendicitis'.
Still unsure, the paramedics asked that I be examined by an obstetrician and a midwife when I got to the hospital.
By now I felt delirious with pain.
'I doubt you're pregnant,' the doctor said, after asking some standard questions. 'But we might just do an ultrasound to be sure.'
He started to set up the machine to do a scan while the midwife felt around my stomach.
But suddenly, a look of concern spread across her face and she asked if she could do a cervical exam.
I agreed, and soon after, she ran over and murmured something quietly to the doctor. He immediately rushed out of the room.
Then she turned to me.
I couldn't believe what she said next. 'There's no time for an ultrasound,' she announced 'You're going to have to push.'
'Push what?' I asked, terrified.
'Your baby,' she replied calmly. 'You're fully dilated and you're about to deliver.'
The room spun as I tried to make sense of what she was saying.
This couldn't be real!
I hardly knew what was happening as I was wheeled into a delivery suite filled with dozens of doctors and nurses.
Someone was holding my hand, while somebody else was telling me to push with the pain...
In just minutes, I felt a sudden sense of relief and seconds later a loud cry rang out in the room.
The doctor was lifting up a screaming little bub and placing it gently on my chest. A baby girl.
Staring down at the tiny pink bundle, nothing felt real.
She looked so fragile as I gently stroked her face with my finger. That's when it hit me.
This perfect baby was my daughter. I was a mum.
I didn't get to hold her for long before she was rushed off for tests.
I was thoroughly checked as well and I sat there in shock as I tried to process what had just happened.
I'd only arrived at the hospital 60 minutes earlier and now here I was with a baby!
As a nurse gave me a phone to talk to James, I struggled to find the words.
'I think you'd better get to the hospital right now,' I said 'I've just had our baby.'
He thought I was joking at first, but when he arrived 20 minutes later he realised it was all very real.
The nurse brought our daughter in from the nursery and James burst into tears as he held her.
It was love at first sight. 'Let's call her Brooke,' he suggested with a smile.
The next few days were a blur as we adjusted as best we could.
Luckily our bub was in perfect health, just a little on the small side at only 2.7 kilos.
Calling all our friends and family to tell them was a challenge.
My mother, Jean, 54, needed a couple of minutes to process the news. But she was over the moon and started making plans to come over and visit.
Of course everybody asks me how I could have not realised I was pregnant.
To be honest I'm still not sure myself.
The doctors think the baby's placenta must have been at the front of my uterus, which can make it hard to feel the baby's movements.
They also tell me that hormones affect people in different ways, which is why I didn't experience the classic symptoms.
As for my lack of belly, it seems I'm just one of those women who don't show much!
But no matter how it happened, I wouldn't change it for the world.
Six weeks on, Brooke is the light of our lives.
We feel so blessed by our surprise arrival.
How could you not know?
Stories like Sarah's might seem unbelievable, but they do happen. Here are some reasons why you might not know you're pregnant.
False negatives - Pregnancy tests you can do at home can give false readings if used incorrectly, read wrong or taken too early. Read the instructions closely.
Menstruation - Some pregnant women experience a period-like bleeding on a somewhat regular basis. These false cycles are rare, and doctors aren't sure why they only happen to some women.
No bump - People carry weight differently and often your body shape will determine how big your baby bump is. Overweight or tall women will show less than petite women.
Originally published in that's life! issue 26 - July 3, 2014