Something happened (or is happening...not sure) with Google again. I noticed the same thing happen to me a few days ago (and other separate times), and I believe others in the forums have mentioned it as well.
From what I understand, it will take a few days or weeks for our hubs to show up (be indexed?) in Google again. (If I'm wrong, someone please give the right answer!). Even today I noticed a few more hits on Google than yesterday, so that's a positive sign to me.
The other times it happened to me, I went from a few hundred views down to zero in a matter of a few days. After a week, the views went right back up to where they were. Let's hope that happens again!