Here are a few gems (reading highlights) from Depression: Looking Up from the Stubborn Darkness, by Edward T. Welch:
It is easy to miss the obvious: depression is painful. It is a form of suffering.
Jesus Christ our Lord once said, “My soul is exceedingly sorrowful, even to death.” There was no sin in Him, and consequently none in His deep depression.
Therefore, depression, regardless of the causes, is a time to answer the deepest and most important of all questions: Whom will I trust? Whom will I worship?
The cross is the only evidence that can fully persuade you that God is, at all times, good and generous.
Don’t think that your case is unique.
If Jesus learned obedience through suffering, we will too.
Creation is to be enjoyed, but we don’t put our trust in it. The only alternative is God himself.
At the cross, Christ has taken your story of misery upon himself and he has given you his story of resurrection and hope.
Perseverance isn’t flashy. It doesn’t call attention to itself. It looks like putting one foot in front of another. But beneath the surface, where few can see the glory, is something very profound (Rev. 2:2, 19). You are becoming more like God. God sees it, and he is pleased by it.