Totally agree. This was one of the most insightful things I've read on this site in years.
EDIT: Hey, what if it's a natural cycle, like tons of other stuff? Normally, it comes and goes, and the sickness is when it doesn't go. Not really a big leap from your point, but something to think about.
Your post, I don't know why, has me in figurative tears. This feels like someone 'gets' what's happening... and to think that I had no idea what I was feeling for all this time was categorized as depression. I hate to say this because it sounds fake and silly, but you know when people say it 'clicks' and they feel like there's a sudden "light"? That's exactly how I felt after reading your post. Don't ask me why, because I don't know.