As you did not say a word about how much you review and think about GMAT problems, I think you need to put some time into summarizing the problems. GMAT is not all about how many problems you cracked. It is more of what you learned from the problems you did right or wrong. So save the time that you work on the problems over and over again. Sit down and think. Try to sort out the points and the way to crack similar problems.