I've seen a number of blogposts and talks recently that talk about depression, burn-out, and other mental problems. One post recommended reading a book. Another one recommended talking to friends and family. These things might help, but I doubt that they actually solve the root cause (looking back, they definitely didn't solve my problems, at best suppress them).
I recommend something different. If you have a mental issue, go see a professional. Take it seriously. I know there's a stigma attached to this, let's try to break through that.
If your leg is broken, you'd probably go to the hospital. With mental issues, you often don't visually see that something is wrong. It might feel harder to justify seeing a professional. Some people are functioning very well while suffering from mental problems. For example, I can often turn my suppressed anger into productivity (alas, the anger still gets suppressed).
It's scary to take that step. I started seeing a therapist about a year and a half ago, to deal with my depression. It's been one the best things I've ever done for myself. If you're suffering from a mental issue, consider doing the same.