sid786 - 3:55 am on Mar 10, 2013 (gmt 0)
That was a really tough read. I feel your pain, as my main sites have lost traffic and ranking in the SERPs. I think March 6-7 we had an update -- although there's no way to confirm that.
Is your site older than 2 years? I think Google is picking on sites that are old. I see a lot of new sites popping up on the result page. Probably Google tweaked their freshness algorithm? Whatever it is, I feel really, really bad.
Sometimes I feel sh*t looking at the earnings, but I'll never give up!