fatigue is the result of resisting love (cal. 660)
We can access the love we resist by visualization. Picture that which you find beautiful (and perhaps unattainable) saying to you "I think you are beautiful," and picture yourself accepting that love and melting into Oneness with it. That which you love also loves you, because that is Our nature, the divine nature that is apparent when the ego is not editing Reality. In this way you allow yourself the power of the experience of love and beauty, which can be ecstatic.
As we progress spiritually, our capacity to love increases. If there is an increase in Self-awareness (see chart below), without a corresponding increase in the experience we allow, then we resist the "fruits" of the truth we have come to know, as if we want truth without the experience of it ("jus' keepin' it theoretical"). Put this way, we can understand the spiritual error by which our fatigue arises. We discovered the truth of power but resist the power of truth.
Since we are aware of truth, correction is only a matter of allowing the corresponding power, as by the visualization technique, above. As we stay close to a true spiritual pathway, a "straight and narrow path," we are balanced and do not incur the pain of resistance to power nor the confusion of resistance to truth.