Depression is definitely a real illness although mental health experts agree that there is no single cause.  There are several types of depression to include Major Depressive Disorder (very common), Post Partum Depression (occurs in women after childbirth), and Psychotic Depression (feelings of sadness accompanied with hallucinations and/or breaks with reality).

Everyone feels sad from time to time but if those feelings have not gone away after a few days you might want to examine other symptoms. 

• Persistent sad, anxious or "empty" feelings


• Feelings of hopelessness and/or pessimism


• Feelings of guilt, worthlessness and/or helplessness


• Irritability, restlessness


• Loss of interest in activities or hobbies once pleasurable, including sex


• Fatigue and decreased energy


• Difficulty concentrating, remembering details and making decisions


• Insomnia, early–morning wakefulness, or excessive sleeping


• Overeating, or appetite loss


• Thoughts of suicide, suicide attempts


• Persistent aches or pains, headaches, cramps or digestive problems that do not ease even with treatment

If you have any of these sysmptoms and they are affecting your daily life and the people around you, treatment for depression may be necessary.