PR is not dead. PR not only depends upon the baclinks. There are lots of factor on which Google decide the PR like contents,keywords and so on.
As time passed by, pages linking to your page loses link value hence the loss of PR. No big deal, get over it.
yeah, never worry about it. many got the same as you, and so do i. keep working will surely it back but up and up. right....lol
now a days page rank is not that important just concentrate on getting good links ur PR will automatically rise..
What's your blog link? How long do you not to update your blog? If too long not to update your blog, PR is sure to be down.