it has happened with all of us so you are not the only one!! my adsense revenue droped from $500 to $150 per day
yes i am sure something is going on from google my keywords positions have also changed from actual not confirmed what is happening
There was an update Yesterday and it is confirmed by none other than matt cutts: http://twitter.com/#!/mattcutts/status/124905069748559872
Yes, since yesterday (14-oct) I have noticed a sudden drop in traffic, about 40% down. My top keywords are thrown back to the second/third pages of Google, while crappy 5-6 pages thin sites are on first page....what an update..grrrreat . When Mr. G will stop playing with their own algo on weekly basis. Just few days back they have already run the Panda 2.5 update on the last week of Sept.