Hi nigina93,
To answer your immediate question: NO - it's not likely that you are getting 'stupid' as each day passes. There is the possibility that you are studying too much though - and that type of over-activity can lead to 'burn out.' 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:
Studies:
1) How long have you studied?
2) What study materials have you used so far?
3) How many hours do you study in a typical week? How many hours do you typically study during the weekend?
4) How have you scored on EACH of your recent practice CATs (including the Quant and Verbal Scaled Scores fore EACH)?
5) What is your exact Test Date?
GMAT assassins aren't born, they're made,
Rich