i did better on the real deal than i had on any of my practice tests. then again, i only took 2 full-length practice tests, and my personality type is such that i thrive under the pressure to perform. the point is that these tests may not be a perfect predictor of how you will do on the actual MCAT.
i really think "psyching yourself out" is a real phenomenon. as njbmd mentions, try not to focus on the score. if it is a constant source of anxiety for you, it will affect your ability to perform in the exam. this is a crude analogy, but for men it's sort of like performance anxiety in bed. you're worried about achieving the desired effect so much that guess what - you don't achieve the desired effect.
try to think in terms of "beating" each test. remember - the correct answer is in front of you
every single time. the correct answers are hidden in the passage or in your brain
every single time. the material for the MCAT is not difficult. in fact, you probably know most of it cold. just be aware that you need your brain to be nimble and up to the challenge.
are you simulating test-day conditions? eating some high-carb snacks at break times? i took some orange juice, a cliff bar and a banana with me on test day and ate a little of each during 2 of my breaks. if you establish a routine like this, you'll be more comfortable on test day -- it will be just like you've practiced.
don't fret about this too much. try to change the way you think about your scores and the way you approach the test. have confidence that you will succeed when it matters.
