I found a wonderful resource for self-screening for anyone who wants to confirm that they have depression or other mood disorders. It is important to know what you are dealing with in life, then you can develop supports and strategies around it. Help is available but often you or people who can advocate for you have to ask for it.
You can go to this Screening Site to take their test. Knowing what you are dealing with makes it less scary, since you can place your thoughts and feelings into a context and find the right treatment for you. I believe Dr. David Burns recommendation to have cognitive therapy as part of a long-term strategy is sound advice.