On top of the nerves, there’s something else going on that I can’t quite grasp. It’s more unsettling, more of a nagging feeling, like something’s just not quite right.

The subway train whooshes into my station, coming to an abrupt and destabilising halt. As the doors fly open, I alight from the carriage and move along the platform, carried by the momentum of the commuters around me. I’m relieved to be getting closer to work, where I won’t have to move around much for the rest of the day – because while the fatigue has lifted enough for me to cope with the demands of everyday life, I’m still far from where I was before my relapse.

Emerging from the underground station into the bright morning sunshine, I find myself more aware of my surroundings than I ever was. Instead of hurrying along the road, face planted in my emails, I make my way along Buchanan Street at about half the speed I might have done previously (not by choice, of course).

I take in the buzz of my surroundings: revving car engines, the whoosh from the brakes of the double-decker buses, the vibrations coming from the subway below, the strum of a guitar from an early-bird busker trying in vain to attract the attention of the passing worker bees. And people all around me. For the first time, it dawns on me how people seem to sleepwalk through their lives, locked on autopilot as they pound the endless hamster wheel of life. Like an early scene from an apocalyptic movie – but in this one, the threat to humanity is that people live their whole lives without looking up from their gadgets, then discover they’ve missed so much of what life has offered them.

As I continue along the pavement, passing by one smombie after another, I’m suddenly inspired to make a change to the lyrics of the song I wrote. I stop momentarily to punch it into my notepad app, then quietly sing back the words I’ve written, ensuring no one can hear me.

‘Just take a moment, open up your eyes, look beyond your gadgets, lift your disguise.’

It’s a pleasant distraction from the nervous churning in my stomach and the awareness that, whenever I try to up my pace, my body resists these instructions like a stubborn mule.

Eventually I reach my office and climb the steps towards the main entrance, my legs feeling like lead, providing an unwelcome reminder that I’m about to face the unknown. Is that the nagging feeling I’m having? No, that’s not it. It will be tough getting back into the game, but I’m determined, and I’ve got a medical opinion that supports my ability to do so.

‘Alex. So good to see you back.’ My manager, Laura, gives me an unexpected but not unwelcome hug when I reach my desk. ‘We’ve missed you.’

‘That’s good to know.’ I hug her back, then turn to dump my bag under my desk. ‘Oh, looks like someone’s sitting here. Was there a desk move while I was away?’