Hi mdella,
To start, the process of taking (and reviewing) a CAT requires a significant amount of energy and effort - and takes time to 'recover' from. This is one of the reasons why you typically shouldn't take more than 1 CAT per week. By taking 4-5 CATs in the week before your Official GMAT, there's a reasonable chance that you experienced some 'burn out' on Test Day. Even if you didn't "feel" tired, any kind of fatigue would likely be at its worst during the Verbal section (since that's the last 75 minutes of 4-hour Exam). Beyond that point, there are a number of other potential explanations for what you experienced, so I have a few questions about how you studied:
1) How many times have you taken the Official GMAT and what were your scores on each attempt (including the Quant and Verbal Scaled Scores)?
When you took your CATs:
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?
GMAT assassins aren't born, they're made,
Rich