I am also taking p5 this December, ma first attempt though, the study text and pass question looks quite bulky too, but am gonna give it all I got, also past questions wud be of help. I think it more about understanding the principles and applying them to real life situations. I believe we would all smile at the end.
I quite agree that another trial may just be what u need, cos its obvious that there has been some improvements, though not a pass, but with hard work and knowledge accumulated from previous paper study, success is much closer than u think. All d best.