'Look at where we are,’ I boasted to the camera.
After panning my phone around to capture the beautiful blue water and clear skies, I sent the video to my family back home in Ireland.
It was New Year’s Eve 2014, and my wife Rita, then 31, and I were at Kings Beach in Caloundra, Qld, with our Scottish terrier, Ozzie.
We’d been in Australia for three months, after I transferred to the Australian Defence Force.
We were due in Brisbane to see in the new year, so after lunch, I grabbed my bodyboard for a quick dip before we had to set off.
After around 10 minutes, I thought about heading back to shore.
But after some wipe-outs, I wanted to end on a high.
Waiting for the next wave, I pointed the board towards the sand, ready to paddle.
When the wave came, it was bigger and stronger than the ones before, and I knew I was going to wipe out again.
Suddenly, my board was sucked down into the water before flipping out from under me, propelling me straight to the ocean floor.
Hitting my head on a sandbank, I was concussed by the blow and disorientated.
Face down in the water, I knew I needed to stand.
But no matter how hard I tried, I couldn’t move.
Still dazed, I figured I just needed a moment to shake it off.
Then, in shock, I suddenly noticed I hadn’t taken a breath in a while...
My heart and lungs felt like they were jumping out of my chest.
I’m drowning! I realised.
Stand up. Roll over. Just do something! I panicked.
‘Are you okay mate?’ a young boy asked, wading over in the waist-deep water.
He turned my body so my mouth and chin were out of the water and I could gasp for air as two beachgoers ran into the sea to help.
Amazingly, they were a former emergency nurse, and a sports medicine student.
Carrying me to shore, they kept my spine neutral as I tried, but failed, to speak.
My eyes stung from the salt water, but I didn’t want to close them.
If you don’t keep them open, you might die, I fretted.
Thinking back to my military training, I assessed my condition.
I wasn’t bleeding, my circulation was okay and I was breathing.
I’m not dying, I thought, relieved.
Someone fetched Rita, who’d been playing with Ozzie up on the grass.
By the time she reached me, I was able to manage a whisper.
‘It looks bad but I’m fine,’ I assured her.
By now, the lifeguards had taken over and paramedics were on their way.
Arriving, they loaded me onto a spinal board and into an ambulance with Rita.
I wonder if we can still make the night out tonight, I thought.
It hadn’t quite sunk in how serious it was.
On the way to the Nambour hospital, they tested my movement and sensation. I could only wiggle my big toe and thumb on opposite sides.
Was I paralysed? I worried.
Whatever lay ahead, I just felt so lucky to be alive.
After an MRI and CAT scan, I was flown to Princess Alexandra Hospital, in Brisbane.
There, I discovered I’d fractured my C3 and C4 vertebrae in my neck and T5 in my back, resulting in an incomplete spinal cord injury.
It meant I was paralysed from the neck down, but since I still had slight movement in my toe and thumb, there was a chance I could regain more, over time.
‘Will I ever walk again?’ I asked.
‘I don’t know – maybe,’ the doctor replied.
Though it wasn’t the best answer, it filled me with hope because it wasn’t a definite no.
Fitted with a halo brace to hold my neck still, I had to stay in hospital, where my fractures started to heal.
At first, I struggled with relying on others to do everything for me.
The spinal cord injury had impacted my bowel, bladder and sexual functions.
I don’t want to be a burden, I thought.
But, refusing to leave my side, Rita made it clear she wasn’t going anywhere.
We’d called my family to break the news about my injury, and they were incredibly supportive.
My brother, Simon, then 26, and my dad, Liam, 55, flew over to help care for me.
‘I’m going to give my recovery my all,’ I vowed to them, throwing myself into hours of gruelling therapy.
Incredibly, after one month, I stood for the first time, and a week later, I took my first step, to the amazement of doctors.
By April, the halo was gone, I’d regained some movement in my arms and hands, and was back home.
Determined to push myself, I started training for a 10 kilometre run, and just seven months after my injury, I crossed the finish line, overjoyed.
Running the entire race solo, I was determined not to give up.
Six years on, I have slightly diminished gross motor function, including the dexterity in my hands.
But Rita and I have two wonderful daughters, Lara, four, and Isabel, two.
It’s hard to believe how far I’ve come.
I’ve been to hell and back, but even if I had never learned to walk again, I’d be grateful every day for still being here.
Billy’s book Unbowed is available now through Big Sky Publishing.