Alex, I don't want to pick a fight either, but isn't the distinction between "depressed" and "depression"? (I have also suffered from Clinical Depression; I did the psychotherapy route, without drugs).
Even in your definition, (quoting from above)
" Major depression is:
Over the last 2 weeks five of the following features should be present of which one or more should be:
1. depressed mood most of the day nearly every day..."
it would imply that a depressed mood that lasts only a few hours or is not nearly every day would still be "a depressed mood", but not necessarily "depression".
In the medical field, we used "depressed" as a state a patient might be in, for example, post-surgically. We do not mean that the patient "has depression", merely that s/he is, for now, depressed.
I myself still have (occasional) depressed moods, but (I hope) I'm over the battle with Depression.
campfire