I have discovered the truth of this in my own experience recently.  As always, Msgr. Guardini puts it all into words very well:

Above all, we must try to understand that faith is itself life and as such undergoes change and evolution.  Faith is not like empirical knowledge, established once and for all, whatever course life may take (like, for instance, the multiplication tables which, once learned, are known for good, irrespective of how we feel).  Faith is effected by the forces of the mind and heart, by judgment and loyalty–that is to say, by the wholeness of our inner life–so that everything which happens in this inner life affects faith.  Therefore, uncertainties, perplexities, and resistances are bound to arise.  Our inner faculties my be exhausted or we may be entering a new phase of life; we may find ourselves in different surroundings and thus be influenced by new contacts.  All this may be unsettling but is fundamentally quite natural and must be treated as such.  Faith and prayer must persevere together, for faith is not a feeling or experience in its own right but a bridge between the believer and God.  This bridge must remain even if the feeling changes or disappears.  Indeed, it is the very nature of faith to persevere, for faith is not rooted in emotion but in character, not in experience, but in loyalty; in short, not in the changeable but in the constant elements of life.  For faith is “the victory which overcometh the world.”  World in this context is not only people and things, events and circumstances outside, but above all we ourselves, our own life with all its tensions, weaknesses, and fluctuations.

So we must not pander to our own weaknesses but, taking firm hold of ourselves, must stand our ground and endure.

If certain articles of faith (such as, for instance, the divinity of Christ or the mystery of the holy Mass) have become strange to him, he must concentrate on other truths which still have meaning for him (such as, for example, Divine Providence or reward and punishment in the afterlife). … The same applies to prayer.  It may happen that the figure of Christ becomes incomprehensible to him and that he therefore finds it difficult to pray to the Son; in this case he should concentrate more on the Father.  … The truths of faith are all interlocked.  Fundamentally there is only one truth–one God in Three Persons, who reveals Himself in Christ and leads the world to salvation.  If one aspect of this truth comes to life in prayer, it sheds its light on the others and gradually they all revive.

Talking things through with  Mary and the Saints often helps me as well.

I’ve finished reading The Art of Prayer.  I’m sure I’ll refer back to it often.  It’s one of those books, like many good Catholic books, that can’t be absorbed all at once.

I’ve begun The Keys of the Kingdom by A.J. Cronin.  I need fiction.  And I loved the movie version with Gregory Peck (wistful sigh).