We need to figure out why your score dropped so much. We also need to know your strengths and weaknesses. Without those two things, we can't come up with a customized plan.
Use this article to analyze your last couple of practice tests, particularly with respect to timing:
http://www.manhattangmat.com/blog/index ... ice-tests/Then come back here and post your analysis. (Note: NOT just the raw data; tell us what you think it all means. The ability to do this is an important skill.)
In particular, I'd like to know this: you said that, on practice tests, you scored 24 to 37 on verbal. Why is the range so wide? Do the lower scores represent earlier tests and the higher ones later tests? Or was there a lot of variability even in your later tests? You need to figure out why (often, variability has to do with timing issues, stamina issues, or both).
You do mention taking your last practice test 2 days before the real test. What did you do the day before? It sounds like you may have done too much in the last few days, which would increase your mental fatigue on the real test.
Note: mental fatigue does not present in the same way that physical fatigue does. You don't feel "tired" in the typical sense. Other things occur. You find that you have to read something two or three times before you understand it. You get distracted more easily. You start to get sick of the test - you just want it to be over. You care less about checking your work, working carefully and systematically - you find yourself picking answers more quickly or skipping steps in the process. Did any of that happen?