Depression can be reactive or clinical.

Reactive depression is a reaction to a situation. Many people are classed as depressed, a blanket term for so many feelings. If you are not clinically depressed what is causing your depression? Are you lonely, sad, emotionally unsupported, afraid? Have you suffered a trauma, grown up in a violent home or the child of an alcoholic. Are you unsure of your sexuality, have low self esteem, or feel isolated?
Talking to a therapist will help you understand and manage your depression and help you to support yourself in a positive way.