First, nobody's going to get the first 8 questions in a row correct - at least not in the normal amount of time. You'd be in the stratosphere, difficulty-level-wise.
Your comment, though, makes me think that you have heard the myth that the first 7 or 8 or 10 questions are the most important and we have to get them right. It's a myth - that's not how the test works. In fact, one of our teachers was taking the test and deliberately got the first 7 questions in a row wrong, and then did the rest to the best of her ability. Instead of her usual 99th percentile score, she scored in the 98th percentile. :)
You also mention that your OG accuracy was 80%, which tells me that you need to learn more about how the test is actually scored (it's not based upon percentage correct). Most people assume that this test is like the tests we took in school, but it's actually very, very different.
In fact, trying to get the first X number of questions right is likely to lead to a lower score in the end, because you will inevitably end up spending too much time on questions that you can't answer correctly anyway (because they're too hard), and then you'll get other questions wrong later in the section that you knew how to answer but missed because you were rushing. And there goes your score.
So. Read this:
http://www.manhattangmat.com/blog/index ... to-win-it/And then this:
http://www.manhattangmat.com/blog/index ... anagement/And start doing what those articles say. If you would like to know more about the scoring, also read the Scoring section of our free e-book The GMAT Uncovered Guide. You can find it in the Downloads section of your student center. If you don't yet have an account with us, you can sign up for free and get access to the Uncovered Guide.
You mention mental fatigue during the real test. Did you take your practice tests under 100% official conditions, including the essays, length of breaks, etc? If you deviated from official test conditions, then you gave yourself artificial advantages, and that would have hurt you most on verbal, which is the last section of the exam.
Did you take practice tests within 5 days of the real test? How much did you do in the last few days before the test? One other major source of mental fatigue is doing too much - burning yourself out - in the last week before the test.
(And if you are suffering from serious mental fatigue, by the way, then whatever you're doing will seem MUCH harder and less familiar than usual.)
If you'd like to get more specific advice about what and how to study, please use the below article to analyze your most recent MGMAT CAT(s), skipping any that were taken under very non-official conditions:
http://www.manhattangmat.com/blog/index ... ice-tests/Then come back here and share your analysis (Note: NOT just the raw data - your actual analysis of the data). We'll help you figure out what to do from there!
