Some physicians are slowly accepting that depression is not always a mental disease but rather a coping mechanism as a barrier of protection against things we cannot handle. Some get treatment never to have it again. Others it is a chemical imbalance in the brain for whatever reason, mostly inherited gene. People with depression, some have experienced great traumas in their life that has affected them to become depressed. And others just do not know the answers why. A good therapist and a Physiciatrist can help you be diagnosed and go from there. Don't be too hard on yourself. It is more frustrating i find to not know why you act a certain way then to know the answer why and then to deal with it. I hope this helps. Blessings.