Hi karert,
To start, since you are so close to your Official Test Date, you should limit your studies to general practice and light review (NO CATs and NO 'cramming') - 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.
Getting a question wrong won't necessarily impact whether you see any additional questions on that same subject or not. Since the Quant section of the GMAT is only 31 questions and certain subjects are more frequently tested than others - and the GMAT is adaptive (meaning that the frequency and difficulty level of the questions you face is based a great deal on how well you are performing) - the more relevant question would be "which 3 Quant topics are giving you trouble right now?"
You cannot 'skip past' a question on the GMAT, so will have to answer the question that's in front of you (even if you have to take a guess) before you receive the next question on the Exam.
After you've taken your GMAT, if you would like to discuss the results, then you should post back here (or you can feel free to PM me directly).
GMAT assassins aren't born, they're made,
Rich