I would have to agree and wait a few days before getting worried. I also lost tons of traffic in the last few days, lowest in years.
The reason I say wait is because for one of my top keywords, my test site that contains nothing but about 50 pages with the same exact pages (except for a few words changed), has overtaken my main site for that keyword.
So this I know wont stay long and if it does I feel sorry for people searching. It seems like they reset the who thing and we must now wait for it to reconfigure.
Just my thoughts....