Depression lies. Keep that in mind when you are going through a depressive episode--- nothing you are feeling during that despair is true. You are worth more than you can even imagine. Here is a great video from Bloggess and author of Let's Pretend this Didn't Happen, Jenny Lawson, talking about what depression has been like for her.
"taking depression medication is no different than taking medication for diabetes, or a heart condition disorder. Just like your body might need medication,... your brain is part of your body"