Depression is really horrible. I have a friend who is bipolar (the new word for manic depressive). He's either on a massive high, with big ideas and plans, confident and on top of his game, or he's crashed in a sea of despair, locked in his room and unable to function.
Daily drugs are OK but what really helps him is therapy - sharing his day to day challenges with a cognitive behavioural therapist. He manages a much more normal life with therapy - the highs are manageable and the lows are not so crushing.
The sad thing about depression is that it is very difficult to witness from the outside. He was a good friend but is very difficult to keep in contact with.
Seek help. You have a disease.
Charlie