Hi gilpali,
I'm sorry to hear that Test Day didn't go as well as planned. When these types of score drops occur, the two likely "causes" involve either something that was unrealistic during practice or something that was surprising (or not accounted for) on Test Day. If you can answer a few questions, then we should be able to figure this out:
When you took your CATs:
1) On what dates did you take each of your CATs and how did you score on EACH (including the Quant and Verbal Scaled Scores for each)?
2) Did you take the ENTIRE CAT each time (including the Essay and IR sections)?
3) Did you take them at home?
4) Did you take them at the same time of day as when you took your Official GMAT?
5) Did you ever do ANYTHING during your CATs that you couldn't do on Test Day (pause the CAT, skip sections, take longer breaks, etc.)?
6) Did you ever take a CAT more than once? Had you seen any of the questions BEFORE (re: on a prior CAT, in an online forum or in a practice set)?
Beyond those questions, I'd also like to know a bit more about your timeline and goals:
1) What is your goal score?
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