Spoon theory
From ActuallyAutistic Wiki
Spoons are a metaphorical indicator of mental energy, derived from spoonfuls of sugar as a measurement of energy. The term spoon theory was coined by Christine Miserandino in a blog post.
The more spoons you have, the more tasks you can accomplish. However, accomplishing a difficult task will consume one of your spoons of energy.
The metaphor has since been extended, with forks (stressors that can dig into you — and you can cope with a few, until it's one too many) and knives (traumas).