If you want to force yourself to work, the only way is to ramp up meaningful punishment for not working. Being fired doesn't serve as such because it's not felt

If you want to force yourself to work, the only way is to ramp up meaningful punishment for not working. Being fired doesn't serve as such because it's not felt daily, it comes all at once. You need a daily dose of reward/pain to form/alter habits. You can setup some reward for being diligent too, it's even better to have both. I say this but, of course, in your place I'd focus on the disease, not the symptom. Maybe search for a more motivating work environment or job position. Maybe do some therapy to investigate your lethargy (if it's intermittent instead of constant, there must be something to it). Maybe just stop working, if you're privileged enough to afford it.