“Happiness cannot be pursued; it must ensue, and it only does so as the unintended side-effect of one's personal dedication to a cause greater than oneself or as the by-product of one's surrender to a person other than oneself. Happiness must happen: you have to let it happen by not caring about it.”- Viktor Frankl

Find someone or some cause/purpose and fully surrender to this person and/or cause. Then you won't think about burnout and you will experience happiness as a side-effect of your surrender.