What happen To My PR

I was wondering today how come I did not able to have any task from PPP wherein when I checked the opps that not available to me some required below 3 PR. I questioned myself, 'till my husband roger told me if I checked my PR recently because it is common in goggle. i was surprise with the result my page rank was dropped from pr3 to PRO how could that be? I was so sad, want to cry. Does it means this is it for me, no more tasks? Hope not, now that I am enjoying doing blog and making extra money. Oh please google what the heck. Any explanation in here.