I'm going through a period of "dryness" now as well. Indeed, I need it; the previous 3 months were more intense than anything I've ever experienced in my life. I need respite, but I am looking forward to the future. These are my impressions:
In my periods of dryness, I used to think that God had abandoned me, or that I was somehow drifting away from Him, but I realize now that these "dry" periods are necessary periods between spurts of growth. He does not change us in any way that circumvents our free will; we are, of our own volition, undergoing internal change to live in imitation of Him. Therefore, the emotional intensity of our experience with God is in proportion to our desire to experience it. If we truly want to be closer to God, there is no way He will abandon us. But because this relationship requires understanding on our part, He waits until we are ready to proceed before He leads us on the next leg of our journey to Him.
I have come to believe that our most ardent periods--those in which we feel closest to Him--are the periods of manifestation, when we receive the grace for which we have been praying. These periods can be filled with insight, love, warmth, fellowship and, often, incredible joy. The periods in between--the so-called "dry" periods--are those in which we prepare for the next period of manifestation, or obvious grace.
When we are in a "dry" period, our prayers, and the intentions and desires guiding them, subtly change, based on the new insights and experiences with which He blesses us. He gives us all the time we need to meditate on these changes and to decide what they mean to us, and to figure out how we want Him to manifest them in our lives. When we are ready, He graces us with a period of spiritual flowering, and our spiritual life is no longer "dry": we take another step forward.
God is never farther away from us than our own hearts. He answers all our prayers for spiritual growth.