The change struck like a bolt of lightning from a clear blue sky. I’d been under the weather for a couple of weeks – nothing major, just a persistent cough, but for some reason I couldn’t seem to shift it. I took a day off work and carried on. Until 19 March, when I woke up and everything was different.

I was tired – overwhelmingly, crushingly tired, as if I’d been up for days, when in fact I’d slept all night – and I couldn’t think straight. When I tried to text my boss to tell him I wasn’t going to be able to make it into work, it took me more than an hour to string a sentence together.

Eventually, I got out a short apologetic message. Then I went back to bed, where I stayed for three days straight. It should have been scary, but I was too tired to be scared. The need for rest overwhelmed every thought or feeling.