I think the only way to give you useful advice would be to know the origin of the depression. I know that, for myself, it was on account of slowly adopting a really nihilistic worldview that began to bleed into, and personally affect me; I didn't even realize I was depressed until I really stepped out and looked at my situation because I had thought it only applied to how I thought and was "outside of me" and therefore unable to affect me emotionally. [Depression does NOT always mean sad!] Self-induced, however, is MUCH different than organic, or one with an unknown source (tricky.)
I'd start by trying to think of why, or what may have potentially caused you to feel this way. Did something happen? Do you just feel frustrated for no reason? Are you experiencing any big life changes (college, marriage, job change, etc.) that may make you feel confused, ineffectual, lost, or helpless? Or is it something that feels like it literally came out of no-where? Like you just woke up one day and felt lethargic, that nothing is worth it, that you just simply don't want to get up?
There are some people that naturally fall into and become content in routines very easily. You're busy, you've many things on your mind, etc. It's easy to forget that you need small changes for your health time and again. After a while, you might feel a sense of general frustration with an unknown cause, which then amplifies and perpetuates the frustration because you can't pinpoint it. It's in these times that a small change is warranted, as it is a pre-cursor to depression. If ignored and left to fester, you'll find yourself inexplicably depressed and when you finally do figure out the cause, it necessitates a BIG change (instead of small; it's proportional to the level [severity] of dissatisfaction/depression) which is harder to perform when you're depressed, but is still the only way out. (vicious circle...) I think this is why we call it a downward spiral, a loop--because it literally is.
I hope you find your way out. Good luck.
