hello @ALL (first post

)
and hello to kaizen (cool username!),
Being clinical depressed myself for 7 years now, I pretty much know what you are going through.
Well, I also think you're suffering from depression. And as it sounds to me, your "brain-chemicals" (=>serotonin) are not balanced. I really do not think that it can be cured without medication. Did you see a psychiatrist or just a general practitioner?
I just want to give you the advise to take massive action NOW. I wasted a good part of my life because I took too little action. Go to see a therapist. It's no shame. Try to find the reasons for your depression. You also have to have some goals for the future and a positive career outlook etc....
One practical advise is to do things that are good for you (like excercising...you said you actually know that these things are good for you). You have to do these things no matter how you feel. If you suffer from depression, even things you normally really like won't give you much pleasure. Do them anyway!
Take action!
That's it for now. All the best!
Martin