Read More: Healthline
"Mental exhaustion isn't necessarily the result of things gone wrong, or any big upset (though it can be) but more likely an accumulation of too much: Too many decisions. Too much work (in not enough time). Too many interruptions, demands, and shifts in attention. Too many things going on without time to pause and restore. This kind of mental tiredness knocks us back when the volume of tasks and activities we've taken on exceeds our capacity to comfortably handle the stress (even the positive stress) of it all."Read More: Psycology Today