The way I see it is: If you put yourself in a situation where you studied 2 to 3 months ahead of time; you studied at least an average of 3 to 4 hours daily and practiced full length PCAT practice exams from Pearson, Kaplan, Barrons, and Cliff; then I would consider that having done your best.
Having said that, if you still performed poorly on some sections of the test then I would recommend retaking college level classes on the sections you scored weak in.
There is no point rushing to take the exam 3 months later only to see marginal gain in percentile. Worse yet, you might see a decrease in some sections. You might loose confidence
All in all, you want to put yourself in a position where you can do your best. So give yourself a chance to do that and set up a realistic schedule where it will work for you.
In my opinion, one should consider setting aside at least 6 months of preparation for the PCAT; 3 months to get mentally ready by taking a few college level classes (biology, chemistry, organic chemistry I, Calculus I) and another 3 months to do practice exams.