I have faced with the same issue. I think it will become stable in few days time. Let's hope that way.
I feel the effect of traffic from search engines. On one rare day, the traffic from Google ceased completely, then returned with vengeance the next day.
Mine have been pretty stable. Had a big jump for one really competitive phrase for a couple days then it settled right back down to low teens where it's lived for a while.
I got emails from two people today reporting that Google was doing really strange things with searches for their main keyphrases. One was searching his city + homes and getting results for a weird assortment of things unrelated to homes, such as a dating service and a tanning parlor.
You sure you guys guys are not logged in and getting personalised search results due to voting (and same for those making such reports) My search results all seem stable for me.