I've had depression last over a year, but with some days worse than others. During depression I'll have days when I can't do anything, can't eat, can't sleep, just lost in despair, and other days where it's not that bad, but I still feel low and like everything is meaningless. It's hard to remember how long any of this lasts for, because when I'm in it it feels like I have always felt that way, and I will always feel that way. I think the longest I stayed in serious depression in one stretch was probably a year or more. It's really so hard to remember because it all blurs together. Most recently, I was depressed from about Nov-Apr, but it never got to an extreme state this time. I'm still not feeling totally good, but it's a lot better. I think I'm usually on the depressive side, so I don't really know what euthymia is supposed to feel like. Maybe I'll never know.