Hello !
See, GMAT is not the only aspect of your MBA application, Yes ! it's an important aspect, but not so important that a less than average performance should affect other sections and other aspects of your applications. Let's keep this first in mind, and then proceed to discuss how we can handle the Quant.
You need to be quick, If you take more than say 2.5 mins to solve a problem, guess ! Remember this GMAT penalizes unattended questions harshly. This is a game, and we should know our strengths and weakness, you should not go into a obsessed cycle where-in you "need" to solve the problem at the expense of the entire test.
Now, for the next 20 days, practice only OG questions, Your aim should be not to leave out the easy questions or get any easy question wrong, you can get 10 Hard questions wrong and your score wont be as affected as you get one single easy problem wrong. That's the way GMAT algorithm works. So, memorize how to solve all the easy questions from the Official Guide.
Don't postpone, give the test, let's complete GMAT and start focusing on the applications. Remember: Your score in one section of GMAT is only a tiny portion of the big picture.
All the best ! Don't be stressed. Have faith and move forward !!