Hi Insiya,
The scoring algorithm on the Official GMAT is far more complicated than most people realize. Since that algorithm is proprietary, no GMAT company has an exact match for it, thus CAT scores can vary a bit based on the 'biases' involved in their respective designs. The most realistic CATs available are the 6 from GMAC (the 2 free CATs, and each of the 2 that come with Exam Pack 1 and Exam Pack 2), so it would be useful to know how you performed on one of those CATS. Once you have that score result, you should post back here and we can talk through what all of this data means.
You might also want to consider paying to reschedule your Exam. While you might not be 'happy' about that idea, it would be preferable to going into Test Day under-prepared, having a bad experience and then having to pay the full fee to retake the GMAT later.
Before I can offer you the specific advice that you’re looking for, it would help if you could provide a bit more information on how you've been studying and your goals:
1) What study materials have you used so far?
2) When are you planning to apply to Business School?
3) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich