My first attempt at a semi-realistic story that uses fantastical elements

In this novel the world goes to shit, plain and simple. Now not overnight mind you. but over the course of a few weeks the majority of all countries collapse, a few months and billions are dead, a few years and war breaks out.

in this story I plan to go into the nitty gritty of how life changes with the introduction of a system, how governments react, and how the main character navigates the turmoil