From an article in Psychology Today on dealing with discouragement.
One common way to help yourself is to think of times when you were in a good place.
When failure discourages you, think of when you’ve succeeded. When depression makes you despair, think of when you were happy.
Recall that these “up” times have followed the “down” ones.
Remember that you have gotten out of holes before — even if it doesn’t feel possible from the deep, hard dirt floor.
We see a good example of this in Psalm 42.
Written during a time of trouble and exile, the psalmist thinks back to better days.
These things I remember as I pour out my soul: how I used to go to the house of God under the protection of the Mighty One with shouts of joy and praise among the festive throng. (Psalm 42:4)
And he says again:
My soul is downcast within me; therefore I will remember you… (Psalm 42:6)
This intentional remembering leads to a breakthrough.
Why, my soul, are you downcast? Why so disturbed within me? Put your hope in God, for I will yet praise him, my Savior and my God. (Psalm 42:11)
When you’re downcast and discouraged, it’s time to remember: Remember God’s faithfulness in the past, and remember his promise for the future.