Very common. Most people don't like this test and have issues when they take it. You're not alone.
What happened when you choked? Did you get so distracted / nervous that you couldn't think straight and made lots of mistakes? Did you mess up the timing and have a big score drop at the end? Both? Other things?
We need to figure out what went wrong so that we can figure out how to fix it. You may know the material and the issue is nerves and/or timing, in which case reviewing all of the content won't actually fix the problem.
6 weeks may still be enough time or you may need more. Given your goal score vs. current score and potential timing and/or anxiety issues, there's a decent chance you'll need more like 8 to 10 weeks, but I wouldn't change that date right now. Just keep your options open.
If nerves are part of the issue, try this:
https://www.manhattangmat.com/blog/inde ... mat-score/If timing (and, let's face it, *everyone* has some timing issues), first read this:
https://www.manhattangmat.com/blog/inde ... lly-tests/Then this:
http://www.manhattangmat.com/blog/index ... nt-part-1/If you'd like, you can use the below to analyze your most recent MGMAT CAT (this should take you a minimum of 1 hour):
http://tinyurl.com/analyzeyourcatsAlso read this:
http://www.manhattangmat.com/blog/index ... -the-gmat/Then, figure out your strengths and weaknesses as well as what you think you should do based on that analysis. Then come back here and tell us; we'll tell you whether we agree and advise you further. (Note: do share an analysis with us, not just the raw data. Part of getting better is developing your ability to analyze your results - figure out what they mean and what you think you should do about them!)
Finally, are you taking a class? If so, make sure to talk to your teacher. S/he will be familiar with your strengths and weaknesses from class and will probably have some good advice for you. :)