After depression is conquered ?

I've been severely depressed for six years now, and have been trying everything to get out of it. It's taking my dreams and hopes away from me and slowly my will to live. There is nothing that triggered the depression, it just sort of crept its way into my life. Everyday for me is a struggle to get out of bed and do everyday things like shower and get dressed. I constantly feel like I'm always just trying to keep my head above the water. I dream of the day of feeling carefree and peaceful. I feel like I don't know who I am anymore. The depression seems like this unseen "being" that has almost complete control of my life. Like it's holding me down, and just won't let me go. Anyway, I'm getting to the point where I'm thinking of living this life for another 5 or 10 years and I can't imagine it. I wouldn't say I'm suicidal, but I can't live this way.
I'm looking for some hope from people who have had a similar experience with depression as I have, meaning that it came on without reason, lasted for over 5 years, etc... I want to know what it's like after you became yourself again, and is that person the same person as the one before the depression?