The Last Suicide Note Ever Written - Short Story

So today I got a writing prompt which this story is based off of:
All people as far as you can see have disappeared from the face of the Earth. Everyone is gone, except you. Write a story describing how you feel, what you will do to survive, and what you will do to stay sane. What happened? How did it happen? Who made it happen?

This story isn't actually in my Point of View, rather a fictional person. I might make a longer story about everything leading to this point, but not sure yet. It would take a long time, and I have tons of writing projects to work on.