Don't laugh, I didn't know I was depressed until I read a pamphlet in my doctor's office from the National Institute of Mental Health. That was during my second bout with depression. If you found this site you are one step ahead of where I was at. I don't think my own medical doctor knew much about depression. I don't think he was ever depressed. Please see someone who understands the problem.

Persistent sad, anxious, or empty moods. Feelings of hopelessness, pessimism. Feelings of helplessness, guilt or worthlessness,
Loss of appetite or over eating and weight gain.
Loss of interest in sex or hobbies or other activities that you once enjoyed...
Thoughts of death or suicide...
Difficulty concentrating, remembering, and making decisions.

Other symptoms may include over sleeping or insomnia. Decreased energy, fatigue, restlessness, irritability. Persistent physical symptoms that do not respond to treatment, such as chronic pain, headaches and digestive disorders. Another type of depressive disorder is manic-depressive illness. This illness is not as prevalent as Clinical Depression.

How do I know if I have depression? Please see your doctor but you can also take this test. http://www.depressioncenter.net/depressiontest/

ALSO PLEASE REVIEW THESE OTHER DISORDERS !!!

A MANIC DEPRESSIVE / BIPOLAR...

References National Institute of Mental Health:

Borderline Personality Disorder or BPD
You really need to look at this one! It effects 5 to 8% of the population and few know about it!

S.A.D.

Seasonal Affective Disorder, Another form of depression researchers refer to as Seasonal Affective Disorder or SAD. If you notice your feelings of depression are tied to the winter months of decreased sunlight and lack of out-door activities, you may be suffering from SAD! The symptoms may be... a craving for carbohydrates... that includes sugars and starchy foods.... Other symptoms include over sleeping... over eating... fatigue... social withdrawal and decreased sexual desires.