How do I know as a disabled person when I am depressed?

Sx of clinical depre. If you have the symptoms you have depression--consult with a psychiatrist for DX & rx.
Lack of interest. Signs of depression are the same for handicapped people- loss of interest in activities that you previously enjoyed, sadness, feelings of worthlessness, thoughts of harming yourself. If you think you are depressed, you should see a doctor and a therapist.