ACT: 27 (1986 or 1987, I don't recall)
MCAT: 30 (2000)
As having been a teacher for 5 years and spending a great deal of time analyzing, writing and preparing students for exams (including standardized), the ACT and MCAT are pretty much exactly alike in their principal measure: Your ability to take standardized tests. This is a completely independent skill. If you are not a good "test taker" then you will consistently do worse than those that are regardless of knowledge base, preparation time etc. So all things being equal and excluding anomolies (illness, error in bubbling answers, dangling chad, etc...) if you have done well on previous standardized tests, you can assume that you will do reasonably well on future standardized tests, and conversely, those who struggled will continue to struggle. This excludes those who actually take the time to improve their test taking skills (rather than just study content) which is quite a different matter entirely, and one that few seem to do.
So relax, you probably did fine, just like you did before. If you didn't do well on previous tests and spent no time finding out what skills you lack, then you may be disappointed with your consistency.
I have met very few test taking "karate kids" who get their butts kicked in the back alleys of practice tests only to win the whole tournament when it really counts on test day.
Best wishes with your results. AND REMEMBER, the MCAT is only one small piece of the puzzle. Keep your focus on the entire application.