Full glad and merry is our Lord of our prayer; and He looketh thereafter and He willeth to have it because with His grace He maketh us like to Himself in condition as we are in kind: and so is His blissful will. Therefore He saith thus: Pray inwardly, though thee thinketh it savour thee not: for it is profitable, though thou feel not, though thou see nought; yea, though thou think thou canst not. For in dryness and in barrenness, in sickness and in feebleness, then is thy prayer well-pleasant to me, though thee thinketh it savour thee nought but little. And so is all thy believing prayer in my sight. For the meed and the endless thanks that He will give us, therefor He is covetous to have us pray continually in His sight. God accepteth the goodwill and the travail of His servant, howsoever we feel: wherefore it pleaseth Him that we work both in our prayers and in good living, by His help and His grace, reasonably with discretion keeping our powers [turned] to Him, till when that we have Him that we seek, in fulness of joy: that is, Jesus.Revelations of Divine Love, ch. 41.
This is helpful to me when, as now, I'm feeling a bit burned out, what with work and other tasks I've taken on, and, after a truly vicious cold/flu thing, depleted. Dame Julian is considerably more inspiring than the AA slogan that tries to make the same point: "Fake it Til You Make it."