Last summer, in the midst of promotional chaos surrounding my new novel The Offing, I cancelled my own London book launch and instead drove to the Chatsworth estate in Derbyshire, a place I had never previously visited, and jumped in the river right in front of the very big house. It was not entirely an act of self-destruction or a plea for help. (No one knew I was there, the river was only five feet deep and I’m no Virginia Woolf.) It simply seemed like a more obvious thing to do than trying to persuade members of the public to buy my book, and an act more broadly in keeping with the spirit of the novel in question and my writing life in general.

Out in the middle of the bracing River Derwent, with one foot hovering over a deeper, much darker, metaphorical void, I reached beneath the first rock I came to and pulled out a large crayfish. I held the creature aloft, as if it were a totem or trophy. Lobster features significantly in The Offing and here was its freshwater cousin, so it must mean something, I thought. Something Very Important.

Facing the fact that such crustaceans have crawled the Earth for at least 100m years, my own ruminations, paranoia and worries suddenly seemed tragically over-thought. For a few moments, that tenacious crayfish brought me back into being and told me that everything was going to be all right. It intimated all this with its probing, beady eyes.

Relating this, I now realise I was perhaps driven half-insane with anxiety, and it was largely my own doing. Writing had put me there in the river, talking to a crustacean while elderly couples in North Face jackets looked on, instead of attempting to charm a smattering of London readers. Even in my drinking days, I never chatted to crayfish.

As the decade draws to a close and I tot up my published work – seven novels, one work of non-fiction, three short poetry collections – only now do I see why exhaustion triggered a tsunami of anxiety that hit so powerfully that I was laid up for several weeks, incapable of doing little but watch period dramas as I lay foetal on the sofa. What I can’t tell you about EM Forster adaptations really isn’t worth knowing.

Shit, as they say, had got real, in a very pathetic, very English way.

Numerous reports suggest we are currently in the midst of an anxiety epidemic, but it is often only evident when it is upon you, and mind and body switch into energy-saving mode. For me, anxiety goes way back. All those years reading Camus, Sartre and Hamsun and still I had failed to see the signs stacking up over the previous months: the rising sense of panic, the narcolepsy-like bouts of sleep at inopportune moments, the way my digestive system went into revolt. There were puking jags, migraines and aching muscles. Food lost its flavour and noises became amplified, so much so that I became fixated on a neighbour’s cockerel that crowed every morning from 3.55am, and which I wanted to strangle. Even the chimes of the local church bells sounded malevolent, as if mocking my shortcomings. Anxiety feels like you’ve had your skin removed.

Every day I was reading articles about mental health awareness – I think I even wrote some – while ignoring my own. I’d seen some friends get sectioned and others struggling, but I thought I was fine. I had a version of myself to sell to the world: that of the fully functioning human being. My GP when I saw him looked worse than I felt – “I’ve not had a holiday in eight months,” he wearily confided through a yawn – and I spent much of my allotted 12 minutes listening to his plight, finally diagnosing him as suffering from exhaustion.

I did what I could. I got out of bed to appear on BBC Radio 4 and then went straight back to it. I did photoshoots in my back garden, as that was as far as I could travel. I dined on rather a lot of tranquilisers before another appearance. I listened to the same two songs for the entire summer (Truth Hurts by Lizzo and Jogging by Richard Dawson). And so it went. To anyone who encountered me during this period I probably appeared fine, but I felt drunk all the time, even though these days I’m teetotal. Other authors sent nice messages secretly relating similar experiences and thankfully I have a wonderfully understanding agent and publicist who were looking out for me.

Courses of counselling mean I now understand the origins of my anxiety, but not how to banish it. I’m not entirely convinced it is possible to rid oneself of anxiety, just as we can’t rid ourselves of joy, excitement or desire, though swimming, meditation, yoga, long walks, CBT, massages, CBD oil, acupuncture and a 13-album box-set by Gong all help at different times. In the end, I’ve learned the only real cures are time spent with my wife and dog, and doing nothing.

Doing nothing is harder than you think. It involves saying no and suspending any sense of guilt at doing so. It involves feeling (though not necessarily being) selfish. It also means missing out on opportunities. Of course, all work is hard, and writing remains the best job in the world, even though it’s not technically a job, because most jobs – at least, until recently – offered sick pay, pensions, workers’ rights and some degree of stability. But the perks are many, chief among them the freedom to be selfish.

Underlying my summer meltdown was something more prosaic: wisdom-tooth problems and endless infections mere inches from my brain, yet every time I got given a surgery date it clashed with promotional opportunities. For my publicist, getting me to do things was no doubt like pulling teeth, yet getting a tooth pulled was all I wanted. The NHS treatment was wonderful, but the surgery was rough: some of my jawbone was removed and I was given fentanyl, a drug 100 times stronger than morphine. I eased into autumn with a swollen head, and nicely off my nut.

It’s at this point in such articles that we might conclude with a brief anecdote to illustrate redemption and a self-congratulatory payoff about how wonderful life is now the author has discovered spin classes and celery juice. This is not one of those pieces. I do feel better, for now. I’m still swimming, I’m writing a new novel. And I’m still aware that anxiety sits beneath everything, like bedrock. It’s a part of me, and especially insidious in the mornings. I think perhaps it’s a part of most of us as we enter the third decade of an utterly traumatic century. It’s wild out there in the world. All we can do is look out for each other and recognise the signs. And stay in bed now and again.

• The Offing by Benjamin Myers is published by Bloomsbury Circus.