Ballswinger, I have had the same thing happen to one of my sites, unfortunately my Googlers were buyers not browsers.
Have you checked to see whether you are still in the index?
If you are then at this stage I wouldnt worry to much, just patience and see what happens at the next update.
Yesterday my site returned at number 1 but has again disappeared.
Although googlebot still visits everyday the cache was showing as Feb 20 and still is.
I think this is just another one of the google blips.
Pr has nothing to do with the serps but if it had disappeared
then I would be worried.