Hi leftfootlucy,
Many Test Takers spend 3 months (or more) of consistent study time before they hit their 'peak' scores, so if you've been studying off-and-on for just a month, then you should not expect to have mastered any aspects of the GMAT just yet. In addition, if you were taking your CATs in an unrealistic fashion, then that could have led to unrealistic, 'inflated' score results that made you think that you were more prepared for Test Day than you actually were. Thankfully, you're actually not that far from a 590+, but before I can offer you the specific advice that you might find beneficial, it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) What study materials have you used so far?
2) How have you scored on EACH of your CATs (including the Quant and Verbal Scaled Scores for EACH)?
3) What were the Quant and Verbal Scaled Scores for your 540?
Goals:
4) What is your goal score?
5) What Schools are you planning to apply to?
6) When are you planning to apply to Business School?
GMAT assassins aren't born, they're made,
Rich