How do I regain my sense of wonder?

Okay, so I suffer from depression. I had a hard and violent childhood and I grew up faster than a kid should. I had a difficult adolescence, filled with sex and drugs, running away, and generally destructive behavior.

I began to climb out of my own personal gutter at around 22. I went to college, got two degrees, and now I have a wonderful wife, 5 furry children that make me happy and amuse me greatly.

The problem, I have been afflicted with melancholy and ennui since my teen years; I have a general cynicism about people; I feel jaded, my desires and passions are blunted, and I lack joy.

I’m not religious. I have an existential view of the world. I don’t believe in the spirit nor do I believe in the infallibility or the eminence of science.

Is there any help for me? Am I doomed to this existence?

Please do not tell me I need to find god. It will not be helpful.