Let me put this line of the song into its literary setting.
As the deer pants for the water brooks, so my soul pants for You, O God. My soul thirsts for God, for the living God; When shall I come and appear before God? My tears have been my food day and night, while they say to me all day long, “Where is your God?”
These things I remember and I pour out my soul within me. For I used to go along with the throng and lead them in procession to the house of God, With the voice of joy and thanksgiving, a multitude keeping festival. Why are you in despair, O my soul? And why have you become disturbed within me? Hope in God, for I shall again praise Him for the help of His presence. (Psalm 42.1-5)
The little 'Bambi' deer in the photo and in the Marty Nystrom song is exactly NOT what the Psalmists are writing. The author(s) are desperate, more like a vagabond, a lonely man, a starved, aching desperado. Their anguish is summarized in the words, "My tears have been my food", "I will say to God, “Why have You forgotten me?", and "Why do I go mourning because of the oppression of the enemy?” As a shattering of my bones, my adversaries revile me." Those are not gentle words of a smiling deer, but the deep, heart-felt cries of man-in-pain. Deep pain. Aches that describe a depressed, down-in-the-dumps singer.
So why is that in the Bible, anyway? Shouldn't a Bible-believer sing happy-clappy songs throughout his days? When someone finds eternal life in Messiah Jesus, shouldn't they have a good life, full of pleasure and without suffering or angst?
The apostle John wrote about the overcoming of the Devil in Revelation chapter 12. "And they overcame him by the blood of the Lamb, and by the word of their testimony, and they did not love their life unto death." The pain of life, in the midst of others' pleasures, that seems to be the fate of those who want to win.
Kreeft continues in that book, "“When the worldly toys in which we foolishly place our hopes for happiness are taken away from us, our foolishness is also taken away, and this brings us closer to true happiness, which is not in worldly things but in wisdom.”
Philip Yancey writes in Where is God when it hurts?, "God does not, in the comfortable surroundings of heaven, turn a deaf ear to the sounds of suffering on this groaning planet. He joined us, choosing to live among an oppressed people-- [Elie] Wiesel's own race-- in circumstances of poverty and great affliction... Jesus did not receive an answer to the questions of cause. "Why? ...why?" he called from the cross, and heard nothing but the silence of God. Even so, he responded with faithfulness, turning his attention to the good that his suffering could produce...Jesus' suffering was not a matter of impotence; he could have called on a legion of angels...God took the Great Pain of his own Son's death and used it to absorb into himself all the minor pains of earth. Suffering was the cost to God of forgiveness."
Suffering is purposeful, but depression? How is that useful? When is that to be relieved?
Maybe this article by Mary Leigh Keith will help. And the links they share at the end, also. You are not alone. We have walked this way before. And we are surviving. And finding God now and then. And that's worth it all. Like a deer, come find the water. The refreshing is in His presence. In that double psalm, it's at the altar. It's where the throngs were. The psalm ends with "hope in God." That conclusion, no matter the attending feelings-- that's where life really is.
What do you think?