Hi Joshua,
You've described two issues that could have very heavily influenced your performance on Test Day:
1) A poor night's sleep can absolutely impact anyone's performance over the Course of a 4-hour exam.
2) You mentioned how you weren't studying that intensely, which makes me think that you were not too rigorous with how you took your practice CATs. Did you take the ENTIRE CAT (including the Essay and IR sections) each time? Did you take the CATs at the same time of day as your Official GMAT? Did you do ANYTHING that would be considered unrealistic and not test-like (taking the CATs at home, skipping sections, pausing the CAT, retaking a CAT, etc.)?
The more you deviate from the reality of Test Day, the more likely your CAT scores are to be "off" (and usually, that means "inflated"). The good news is that both the Quant and Verbal sections are standardized and predictable, so you CAN train to score higher in the Quant section (and even pick up some points in the Verbal). However, you CANNOT continue to afford to study "your way" - you'll have to make some adjustments and likely invest in some new materials.
Given your current scores, you could be ready to retest in a month, so the investment of time, money and energy wouldn't necessarily be too great. Given the specific need for Quant resources, I would suggest the EMPOWERgmat Quant Score Booster - most of our Clients complete that Study Plan in under a month, but you will need to set aside the necessary time to get through all of the materials. We have a variety of free resources on our site (
www.empowergmat.com) that you can use to "test out" the Course.
GMAT assassins aren't born, they're made,
Rich