Good luck on PrepTest 84. You're literally taking an undisclosed practice test that some person will be taking in their basement in a few years. Therefore, the test you will be taking tomorrow could just as easily have been your highest scoring practice test.
Take the test EXACTLY like you've taken any other PrepTest because that is exactly what it is.
Take the June test: you said it yourself that your 169 was only one data point out of a bunch. If you've been doing everything properly, you'll likely score somewhere in your usual range if you approach the test like you always do.
I think the nerves of the test are getting to you. If you're making mistakes during logic games when you usually don't, it may be because the test is approaching and you're trying to be perfect. The fact that you feel "exhausted" indicates this. Just take the test how you've taken it over the past few months.
That is what defines you, not just a 169 and a few nervous glitches getting closer to the test. Plus, the fact that you are scoring much lower on your last test means you'll likely score higher on the real one :wink:
Just review your mistakes and do your best.
P.S. If you legitimately feel nervous and feel as if the nerves will interfere with your test, then delay. Otherwise, just take Pretest 84 on the 11th.