The Spoon Theory written by Christine Miserandino
The above link will take you to the page with the article. There is a link on that page which lets you download a PDF instead. It explains the spoon theory.
This theory has been taken by many of us disabled folks and turned into cultural jargon. Being in a crip friendly place I will often hear a friend talk about spoons and it is just understood. It is easier than explaining mental, physical, emotional, and other types of energy and expenditure and how they apply to sick/disabled/crip/etc folks.
Read it. Enjoy it. Now you know what I mean when I say spoons.