I agree with all the above. Don't do anything related to the MCAT except making sure you know where your testing center is. I woke up at the same time I would for test day, made myself a nice breakfast, and then went and saw Avengers: Infinity Wars since it came out the week before my test. I was home by 5 pm, asked my roommates to be extra quiet (and then bought them pizza the next day for agreeing), and went and rocked the test. If you're hitting your target scores, more studying won't help, but relaxing and being fresh definitely will. Good luck, OP!