Burned out at work

The suttas know the lute strung too tight and the flood crossed by neither stopping nor pushing; they also know that thinking for too long tires the body and that a tired body unsettles the mind. Effort in the canon is tuned, not maximized. The passages here are about that tuning, about the second layer of exhaustion that comes from resenting the first, and about mindfulness of the body as a place to stand when nothing else holds. They do not diagnose depression, which can look like this, and they will not decide whether to leave the job.

What the suttas say

Still, thinking and considering for too long would tire my body. And when the body is tired, the mind is stressed. And when the mind is stressed, it’s far from immersion.
The Buddha on overwork before awakening — even wholesome thinking, kept up too long, exhausts the body and then the mind.
Where this stops: Said of wholesome thoughts pursued too long; it is about pacing, not a warning against reflection.
MN 19:8.8–8.10 · Two Kinds of Thought
“But when your harp’s strings were tuned neither too tight nor too slack, but fixed at an even tension, was it resonant and playable?” “Yes, sir.” In the same way, Soṇa, when energy is too forceful it leads to restlessness. When energy is too slack it leads to laziness.
The classic instruction on balancing effort.
AN 6.55:6.1–7.1 · With Soṇa
It’s when a mendicant—gone to a wilderness, or to the root of a tree, or to an empty hut—sits down cross-legged, sets their body straight, and brings mindfulness to the present. Just mindful, they breathe in. Mindful, they breathe out. Breathing in heavily they know: ‘I’m breathing in heavily.’ Breathing out heavily they know: ‘I’m breathing out heavily.’
The first instruction in the Satipaṭṭhāna Sutta, in full and without elaboration.
MN 10:4.2–4.4 · Mindfulness Meditation
When an unlearned ordinary person experiences painful physical feelings they sorrow and wail and lament, beating their breast and falling into confusion. They experience two feelings: physical and mental. It’s like a person who is struck with an arrow, only to be struck with a second arrow. That person experiences the feeling of two arrows. In the same way, when an unlearned ordinary person experiences painful physical feelings they sorrow and wail and lament, beating their breast and falling into confusion. They experience two feelings: physical and mental.
The distinction between the pain and the reaction to the pain.
Where this stops: The sutta grants that the first arrow lands on everyone, including the awakened.
SN 36.6:1.5–1.13 · An Arrow
“Good fellow, how did you cross the flood?” “Neither standing nor swimming, respectable sir, I crossed the flood.” “But in what way did you cross the flood neither standing nor swimming?” “When I stood, I sank under. When I swam, I was swept away. That’s how I crossed the flood neither standing nor swimming.”
The shortest statement of right effort in the canon.
Where this stops: About effort in practice, the crossing itself; not a picture of caring for someone. Never use it to tell a tired carer they are straining or should stop.
SN 1.1:1.4–1.9 · Crossing the Flood

Bring your own situation.