In HUMAN ALL TOO HUMAN (SHAMANIC DOUBLING)

I note that Nietzsche speaks about an imperious inner force that makes one sick whenever one does not follow one's inner task. One has to get back in tune with it, otherwise one gets sick. One must burden oneself more heavily in order NOT to succumb. This inner knowledge is fundamental to human development. How different is the contemporary philosophy of popping a pill for what ails you.

 Lonely henceforth and badly mistrustful of myself, I then took sides, not without indignation, against myself and for everything that hurt and was hard just for me: thus I found the way again to that courageous pessimism which is the opposite of an idealistic mendaciousness, and also, it seems to me, the way to myself, to my task ... That hidden and masterful something for which we long do not have a name, until finally it proves itself to be our task—this tyrant in us wreaks horrible revenge for every attempt we make to dodge or escape it, for every premature resignation, for every acceptance of equality with those among whom we do not belong, for every activity, however respectable, which distracts us from our main cause—indeed, for every virtue which would protect us from the hardness of our innernost responsibility. Every time, sickness is the response when we want to doubt our right to our task, when we begin to make things easier for ourselves in any way. Strange and at the same time terrible! It is the easing of our burden which we must atone most harshly! And if we want to return to health afterward, we have no choice: we must assume a heavier burden than we ever carried before ...

(EMPHASIS MINE)
http://www.thenietzschechannel.com/works-pub/ncw/ncw.htm