It was during the course of reading the Daily Office readings for today that I read Psalm 77. Asaph has a struggle of confidence in the Lord within his heart causing him to waver, displayed here (man, have I been here before):

Psalm 77:4–9
You hold my eyelids open;
I am so troubled that I cannot speak.
I consider the days of old,
the years long ago.
I said, “Let me remember my song in the night;
let me meditate in my heart.”
Then my spirit made a diligent search:
“Will the Lord spurn forever,
and never again be favorable?
Has his steadfast love forever ceased?
Are his promises at an end for all time?
Has God forgotten to be gracious?
Has he in anger shut up his compassion?” Selah (ESV)