Hi dina98,
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) Did you take the ENTIRE CAT (including the Essay and IR sections)?
2) Did you take them at home?
3) Did you take them at the same time of day as your Official GMAT?
4) 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.)?
5) Did you ever take a CAT more than once?
The lack of sleep and anxiety you've described could also have hindered your performance. Taking a CAT two days before your Official GMAT was also NOT a good idea (since taking a CAT requires a significant amount of effort, you might have experienced some 'burn out' before Test Day).
1) What were your two Official GMAT scores (including the Quant and Verbal Scaled Scores)?
2) What is your goal score?
3) When are you planning to apply to Business School?
GMAT assassins aren't born, they're made,
Rich