My PageRank is Back to Zero

It was last week of October when I noticed the my pagerank increased to two. And now, just after three weeks, about two days already, my pagerank is back to zero again. Maybe it's true that Google's latest pagerank update is meant to penalize sites with excessive paid links. If this is true, maybe that is the reason because I ran PayPerPost in this blog. But this will not stop me from doing post sponsored by PayPerPost because even those are sponsored, I can say that I honestly give my opinion in every post, sponsored or not.