I almost forgot to look away as the doctor drew my blood. Then she checked my heart.

“It’s quite fast,” she said. “But that’s probably because of your journey here, based on what you’ve told me. You took the Tube?”

The NHS GP on my street had a two-week waiting list — to speak over the phone. The private GP saw me the day I called. She was based in a skyscraper.

I was desperate for answers. Why did I feel unbalanced on the Tube? And then in crowds? How was this physical sensation a symptom of anxiety? It was surely going to be too much for a blood test to answer.*

Outside the skyscraper, I realised I hadn’t eaten. I ate a banana by the side of the road and felt better. Then I took the Tube home.

Days later, I took a guided tour of the west side of Highgate cemetery, built by the Victorians to keep the bodies far away from central London. In the terrace catacombs, those feelings returned. I leaned to my left as the ground swallowed me up. I couldn’t help but see the dark humour in it as the shelves of coffins propped up my body.

*It was.