I didn't feel brilliant when I woke that day, but passed it off.

The first five kilometres were uneventful. It's a beautiful run that starts just outside Katoomba, drops down to the Megalong Valley floor, then up 12 kilometres of winding track to the top of a ridge and on to Jenolan Caves. It's 45 kilometres in all.

My friend Sue and I had run it a few times by then. We fell into a familiar pace and yapped about everything and nothing. Then we hit the 5 kilometre mark and I staggered a little. The best way to describe what it felt like is to picture the cartoon character Wile E. Coyote when he knows he's about to die and the colour drains out of him, from top to bottom, leaving a grey outline. The energy just drained from me.

My friend - who has never lived down what happened next - said "Are you right?"

I said "No, but you go. I'll have to go with this for a bit. I'm fine."

She said she'd tell the first aid crew at the next drink stop that I was on my way and went on. I was fine with that. I didn't want to talk and I couldn't keep up.

By the time I ran the Six Foot Track that day I'd been writing about child sexual abuse in the Catholic Church for four or five years. The marathon, held in March each year, came to represent more than just an annual run. It's hard, it has a tough mountain climb in the middle of it, and when the church stuff seemed overwhelming there was something solid and beautiful about running that event through Australian bush that I drew on long after it was finished.

So I wasn't going to stop that day.

I have a few clear memories - looking at a ditch and visualising myself in the foetal position at the bottom of it; focusing so hard on staying upright during a particularly steep section that a horn blown by an enthusiastic supporter broke my concentration like a physical assault and I thought I'd throw up. And I remember feeling so bad at one point that I stopped, assessed how I felt - appalling - but decided I could keep going because if I was assessing myself, my mind was still functioning. Possibly not the best reasoning, but it seemed sensible at the time.

You have seven hours to finish the Six Foot Track. At a certain point I gave away the idea of finishing within that time. The goal was just to finish.

The final part of the Six Foot Track is a wild descent on a rock-strewn path on the side of a cliff where you can end up hurtling to your death if you wrong-foot it. I can't say I've ever thought of it being much of a risk because by that stage you can hear the crowd at Jenolan Caves down below.

I was exhilarated that day to make it to the end, within the seven hours, knowing how crap I'd felt. It is an extraordinary thing to push yourself and keep pushing to see what you've got in you.

It was just a run and nothing would have happened if I'd wandered off and said I was too sick to go on. I was later diagnosed with bronchitis, which I acknowledge adds a layer of stupid over the whole thing, but the extremes of that day set me up for a couple of gruelling years before the Royal Commission into Institutional Responses to Child Sexual Abuse was established in 2012.

I'm writing about it today because that run was an exercise in willpower, and trusting that I knew myself enough to push hard.

It's been willpower since late 2016 that's kept me working as a journalist, dealing with two extremely demanding areas - the twin tragedies of institutional child sexual abuse and the abuse of Australian women implanted with pelvic mesh devices, that's been not much more than one long experiment on women's bodies by doctors and device manufacturers within a disgracefully compliant health system.

That willpower has gone and I resigned last week after 40 years as a journalist. I'm not ill. There's no other job in the wings. This is just a job that requires - demands - motivation. And when it's gone, it's gone.

A bishop's stupid comments a few weeks ago set in train a series of events that ended with a resignation. There will always be stupid bishops until Catholics rise up and reclaim their church. There will always be stupid politicians willing to back churches because it's easy and there's votes in it. There's only so much stupid, though, that I can take. After 14 years of writing about the Catholic Church's crimes, I'm going to leave stupid to the people who can't seem to see it.

My advice to Catholics trying to reclaim their church? Note how quickly and easily bishops, the Pope and the Vatican were able to dispense with long-held traditions and rites in the face of a pandemic, despite their martyred arguments against removing traditions and rites that allowed church men to rape children on an industrial scale. Celibacy and confession are two that come to mind. And why not try women priests - because haven't the blokes in frocks done such a good job?

I've worked with some truly extraordinary people over the past 40 years, including the Newcastle Herald editor who committed the newspaper to campaigning for a royal commission, Chad Watson, and the current editor, Heath Harrison, who has helped me work for the past three years through some of the most difficult periods of my career. The other extraordinary people are the tens of thousands I've met as a journalist, including work colleagues and members of the public. My thanks to each and every one.

The media cops it, rightly at times, for its excesses. But if it's just you versus governments, churches, banks, companies, spivs or conmen, it's nice to know journalists have got your back.

Joanne McCarthy led the Newcastle Herald's campaign for a royal commission into institutional child sex abuse. She filed countless stories through years of fearless investigative reporting under the headline 'Shine the Light'.

You can read the full Shine the Light archive here.