Boggled by my score -600

Hi,
I was doing self preparation for a couple of months mainly from OG and Kaplan.
In the two pearson mock's i got 670 & 660.
Gave my Gmat today and scored 600!

Here's what i think went wrong.

AWA: Did pretty well i guess, 4-5 paragraphs and as per the templates everyone follows.

IR: Attempted all questions and was fairly comfortable.

Quant:
During my mocks i was constantly getting 2-3 question wrong in the first 10 questions,my instructor told me to get the first 10 right and i ll improve
...

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