Hi anurag16589,
Based on what you've described, there are a couple of ideas to discuss:
1) A poor night's sleep right before Test Day would likely impact anyone when they took the Official GMAT (and 2 days in a row of poor sleep would almost certainly make things worse). You might benefit from more of a nighttime 'routine' - such as meditation, drinking green tea, taking a low-dose of melatonin, etc. Of course, you should discuss this issue with your doctor before you make any choices.
2) GMAC has publicly stated that the Official Score that you earn on Test Day is within +/- 30 points of actual ability. I bring this up because your two Official GMAT Scores are fairly close to one another, which means that you essentially responded to each Exam in the same general ways. You did certain things consistently well, but you also made certain consistent mistakes. If those Scores are representative of your current ability level, then it will take some significant improvements to how you handle the Exam to hit your goal score.
3) A 750+ score is essentially the 99th percentile - meaning that 99% of Test Takers will never hit that score no matter how many times they take the GMAT. Thankfully, no Business Schools actually require a score that high, so your MBA goals won't disappear if you don't get to that level. Remember that your real goal is to get into your first-choice Business School - and that requires a competitive GMAT Score, a strong OVERALL profile and your ability to properly 'market yourself' to each individual School that you apply to.
All of that having been said, I have a few questions about how you've taken these CATs:
1) Did you take the ENTIRE CAT each time (including the Essay and IR sections)?
2) Did you take them at home?
3) Did you take them at the same time of day as your Official GMAT?
4) Did you ever do ANYTHING during your CATs that you couldn't do on Test Day (pause the CAT, skip sections, take longer breaks, etc.)?
5) Did you ever take a CAT more than once? Had you seen any of the questions BEFORE?
GMAT assassins aren't born, they're made,
Rich