I would take leanna's answer with a grain of salt - at least seeing what her position is...
in fact i would say that most people overestimate the effects of the GMAT score on their future lives and career.
more specifically to your questions:
it seems that not only that you exhausted study material but you mainly exhausted yourself. psychologically, and possibly physically.
- my first and foremost advice - TAKE A BREAK. two weeks without gmat on your mind will do wonders to your score.
- i don't know exactly what studying strategy you used and where exactly you stand... but based on the fact that you exhausted materials - it is time to focus and consolidate your preparation:
I would focus only on GMAT prep and OG, doing them all over again - comparing your new results with the ones you previously made.
then do it again.
and again.
until you are so familiar with the questions and the lines of reasoning, that you solve them without a single mistake, still in the time boundaries you set for yourself (on the OG).
when you make a new mistake, ask yourself why you did it wrong this time as opposed to previous times. if you repeat an old mistake reread the explanations (OG explanations are the best... and can be supplemented by this forum).
this strategy will also boost your self confidence, which is probably THE MOST IMPORTANT SINGLE FACTOR in gmat success.
do some sport. don't over-invest time studying. keep your life balanced.
you'll do just fine.
good luck.