If you struggle with depression, you might appreciate this principle from the book of Genesis (Gen. 4:3ff):
Both Cain and Able brought sacrifices to God, but God only had regard for Able's sacrifice.
Hmm.
This made Cain mad. And it put him in a deep funk.
When God saw this, He asked Cain why he was angry and depressed.
And He gave him something to ponder about getting out of the state he was in.
He said:
"If you do well, will not your countenance be lifted up?"
"And if you do not do not do well, sin is crouching at the door and it's desire for you, but you must master it."
With these words, Cain had a choice to make about how he was going to handle his depression...
Either do what is right by faith and be lifted from his distress, or follow some bitter course and come under the domination of sin.
And herein lies the important principle...
When the story of your life doesn't go as you think it should, be careful...
The temptation to nurse resentments may come on you strong... making you vulnerable to sin that's constantly seeking to get an upper hand.
But if you persist in doing what you know to be right -- by faith -- God will lift your spirits.
There is something magical that happens when you set out to do good... trusting God... even though inside you feel the right to be gloomy!
So if you're in a state of glumness, here's the best thing you can do...
Look for some good you can do today... and do it.
"... the righteous will live by his faith" (Hab.2:4).