I thought this quote by St. Francis de Sales was very helpful.  As he also says: "In prayer we must not seek the consolations of God, but the God of consolations."

"The mere comfort of a prince’s presence or that of someone we greatly love makes watching, pain, and toil a delight, and danger itself desirable.  But nothing is so grievous as to serve a master who knows nothing of our service, or if he knows about it, still gives no sign that he is satisfied with it.  In such cases, love must be strong, because it stands by itself alone, unsupported by any pleasure or any expectation.  Thus is sometimes happens that we have no consolation in the exercises of sacred love, because like deaf singers, we do not hear our own voices and cannot enjoy the sweet melody of our song.  Besides this we are oppressed by a thousand fears and troubled by a thousand false alarms that the enemy raises around our heart, suggesting to us that perhaps we are not pleasing to our master and that our love is fruitless- yes, even that is false and vain, since it produces no consolation.  Then, Theotomis, we toil not only without pleasure, but with very great distress, since we see nei9ther the good of our labor nor the satisfaction of Him for whom we labor.

…It is now, my dear Theotomis, that we must show unconquerable fidelity to the Savior, serving Him purely for love of His will, not only without pleasure, but under this deluge of sorrow, horror, dread, and attack, as did His glorious Mother and St. John on the day of His Passion."