Hi zangetsualpha,
From what you describe, you are not facing any immediate application deadlines, so there's no 'rush' for you to take the GMAT in 10 days. Thus, if you don't feel completely 'comfortable' with the Exam yet, then you might consider paying the rescheduling fee and pushing back your Test Date (you would have to make that choice at least 7 FULL days before your current appointment though).
Assuming that you want to take the GMAT as scheduled, then you have to be careful about trying to do too much studying in these last 10 days. "Cramming' generally does NOT lead to great results on the GMAT, so while you might want to do some additional Verbal work, you should not try to study too much on each individual day. You also have enough time to take one more practice CAT - but that CAT shouldn't be taken too close to your current Test Date. In the last few days before your Exam, you would be better served by getting some extra rest so that you can go into Test Day calm, clear-headed and ready to work.
As far as the subjects that you should focus on during these final days, some review of your prior work is warranted. "Review" is an exceptionally important part of the GMAT training process; your ability to define WHY you're getting questions wrong is essential to defining the areas that you need to work on (and the specific things that you need to 'fix'). As such, I'd like to know a bit more about your last CAT. While a full Mistake Tracker would provide a lot more information, there are some basic questions that you should be able to answer (and the more EXACT you can be with your answers, the better):
After reviewing each section of this recent CAT, how many questions did you get wrong....
1) Because of a silly/little mistake?
2) Because there was some math/verbal that you just could not remember how to do?
3) Because the question was too hard?
4) Because you were low on time and had to guess?
5) How many Verbal questions did you 'narrow down to 2 choices' but still get wrong?
GMAT assassins aren't born, they're made,
Rich