The sad part is Yeah I have done it...
Assumptions has been a problem for me... I have noticed that in my exams and in my practice of the OG questions, assumptions was a challenge. The first question was an assumption (in gmatprep) and i got it wrong!!4 RC questions wrong and 3 sentence correction questions were wrong. I timed the exam very badly. I had 3 minutes and 10 questions left... Which is terrible!! So I started guessing most of them.
The math section I found it tough but I managed to get a 42. My strike rate was just about OK in the initial questions (4 wrong out of 15) (2 of them were questions 12 and 13 and 2 of them were questions 4 and 9).