If you're from Google, could you take a real look at this issue. There's a bug here or Google changed something in its algo that's hurting us (but then adsense should tell us what's wrong, 90% earnings drop that's no matter to laugh at)
Are you at Adsense already on vacation for the fourth? And I guess you won't be back before next Monday? Hurray, we're losing #*$! load of money meanwhile.
Please get the tech team to check what's happening.