What to do when depressed?

Depression is a complex situation because it integrates many aspects, for example: if I feel anger, it is because I feel powerless, thus frustrated that you cannot change “the thing that keeps you depressed”. Or, If I are am an egoist person, then others will start to stay away from me because I am bitter, self-centered, and I will become lonely although surrounded of people.

How does perception affect my thoughts?

Do the voices inside my head control me or do I control the voices? Those voices are conditioned by my past experiences. I see a tree. I know it is a tree because someone told me it was so. I am not focusing. I believe there is a man standing beside it, but I focus and no one is there.

Was it my mind or my senses?