Hi glatzekatze,
From what you've described, you sound rather 'impatient' about this whole process. Many Test Takers spend 3 months (or more) of consistent study time before they hit their 'peak' scores. During that time, it's important to take FULL-LENGTH CATS (with the Essay and IR sections) at regular intervals (1 FULL CAT every 1-2 weeks). You've taken 3 CATs in 4 DAYS. That was NOT a good idea. It also sounds like you're rushing through each CAT, which is also NOT a good idea. Each CAT is a 'measuring device'; when used correctly, it will give you a reasonable score assessment and point out your strengths and weakness.... but taking CATs won't make you a better Test Taker. The type of improvement that you're looking for comes from learning/practicing Tactics, doing practice problems, reviewing, etc... then you take a CAT to see how well you've improved.
Based on the little information that you've provided, I think that you'll likely need 2 months of consistent, guided study to hit your score goals.
1) Did you take the FULL CAT each time (including the Essay and IR sections)?
2) Did you take them at home?
3) Did you take them at the same time of day?
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?
GMAT assassins aren't born, they're made,
Rich