Everything Happens So Much - Andrew Hunter Murray

Esme Good is an entirely unremarkable young woman working a dead-end job in a city much like this, in a first draft universe that lies forgotten in one of the Creator's cosmic drawers.

Through one of the slightly more surprising quantum coincidences in recent memory, Esme ends up deleting every other possible version of herself in every other possible reality - leaving Esme with the somewhat troubling realisation:

There is only one of her.

This makes her not only the most important person in this, or perhaps any, universe - but it also makes her the target of an inter-galactic (wo)manhunt.

We don't have time to get into exactly why that is - but to remedy it, she has to somehow make an appointment to meet our maker and ask if they wouldn't mind terribly fixing it, her, the world, and everything in it while they're at it...