Depressed because of a dark world?
Have you ever seen people reveling and enjoying sin and just felt like it was too sad to witness? Has it caused your soul anguish? Perhaps loved ones, even? Habakkuk was surrounded by evil and it didn't seem to him that God was doing anything about it.
"How long, O LORD, must I call for help, but you do not listen? Or cry out to you, "Violence!" but you do not save? Why do you make me look at injustice? Why do you tolerate wrong? Destruction and violence are before me; there is strife, and conflict abounds. Therefore the law is paralyzed, and justice never prevails. The wicked hem in the righteous, so that justice is perverted." (1:2-4)
We can feel like this. Take ISIS. Horrible. Yet because of that evil, many are reporting that more Muslims are converting to Christianity now than in the past 14 centuries. God's will, as He told Habakkuk, IS being accomplished. Don't be dismayed, and don't be overtaken by shock and awe. Sometimes evil does surround us, but as General Chesty Puller said, "That simplifies the problem." And it makes our opportunities for good that much greater in number.