Hi OndrejGMatTaker,
The scoring algorithm on the Official GMAT is far more complicated than most people realize. Since that algorithm is proprietary, no GMAT company has an exact match for it, thus CAT scores can vary a bit based on the 'biases' involved in their respective designs. In addition, there are a variety of factors that can impact your performance on a CAT/mock, including the type of Exam that you're using, the time of day that you start the Exam, the testing conditions, how well-rested you are, etc.
It's possible that you had a 'bad day' when you took this most recent CAT - but it's also possible that some of your other CAT results were 'inflated', unrealistic Scores. The immediate issue is clearly whether you should stick with your current plan to take the GMAT in 2 weeks. We'll need to better define your studies in more detail before we can decide either way.
Before I can offer you the specific advice that you’re looking for, it would help if you could provide a bit more information on how you've been studying and your goals:
1) Were your 1st and 3rd CATs the two free Official GMAC CATs from
www.mba.com or some other 'brand' of CAT/mock?
2) On what dates (or approximate dates) did you take EACH of your CATs/mocks?
3) Are you planning to take the At-home GMAT or are you planning to take your GMAT at a Test Facility?
4) Have you actually scheduled your Official Test Date yet (and if so, then when is it?)?
GMAT assassins aren't born, they're made,
Rich