What do you call a non-fiction short story?

Because to me, "story" implies fiction. But calling it an "essay" seems too formal, too academic.

I only ask because I thought I should probably do something with my one-time attempt to be Dave Gorman, the non-fiction short story (or essay if you'd prefer) about what happened when I tried to live for a month without using any supermarkets chains.

Yes, Tesc-No - Living without supermarkets is now available for your Kindling pleasure, and joins the growing number of non-fiction titles in my back-catalogue. And when I say "joins", I mean "doubles".

I may have appropriated a logo there...

Narrative. Maybe a non-fiction short story is just a narrative.