What is Fading?
You are operating at a fraction of your usual capacity, and you can feel the difference. Tasks that were once easy now require real effort, and your enthusiasm is reduced. This is a signal to conserve and replenish before the tank empties.
When you might feel fading
Fading is a specific form of running low, which itself is a type of depleted. You might experience this feeling in situations where depleted is present, particularly when the circumstances align with the nuances that define fading.