The practice NBMEs aren't always predictive. It's hard not to get discouraged over a disappointing score but that doesn't mean it's what you'll get on test day. This close to the test, try focusing on brushing up on stuff that you already mostly know. Pharm and micro are always places where it's easy to forget stuff or, conversely, to pick up a couple of extra points. Also review topics that you know you've missed before (e.g. if there are diseases you tend to mix up). If there is stuff you just straight up don't understand, don't delve into it at this point--it's not the best use of your time. Don't study the night before the test; try to relax and do something you enjoy. good luck!