Hi, sorry for the delay.
Both verbal and quant dropped on real test day - there wasn't one section that dropped a ton. Also, you didn't drop a ton in general - you were only 30 points below your GMATPrep score of 580.
Did you take your practice tests under 100% official conditions? Did you do the essays? Did you stick strictly to the timing and NEVER use the pause button? Did you limit your break time to the officially-allowed times? Giving yourself artificial advantages could account for the modest score drop you experienced (eg, if you were skipping the essays, then you weren't really prepared for the stamina needed - you don't get to start quant till after an hour of writing, and your practice tests would already have been over by the time you started verbal on the real thing!).
In terms of more detailed advice, we need more data from you. Use the below article to analyze a recent MGMAT test. If your most recent test was taken under very nonofficial circumstances, then use the test before that one.
http://www.manhattangmat.com/blog/index ... ice-tests/Then come back here and tell us your
analysis (not just the raw data itself). We'll tell you whether we agree and what we think you should do from here. (Also - is your goal score 600+? Or were you just hoping to get that last time, but your actual score goal is higher?)