I was inconsolable after my MCAT. The PS was brutal. A lot of calculations and I ran out of time and ended up having to make 10-second snap judgments on the last 5-6 questions. Wasn't confident in a lot of the answers I did spend time on. I seriously considered just walking out after that section and not finishing because I would have put my life savings on having gotten like a 7-8 in that section. Made myself finish. Thought VR was fair as far as verbal goes, and that the BS had a lot more orgo than the practice tests (and since bio is my strong subject, more orgo meant less bio and thus a harder section). I was averaging about a 35 on the practice tests, but thought that the real MCAT was a quadrillion times harder (and not just because of the stress/time factor, I legitimately thought that the passages were much more difficult). I cried the whole way home in the car, and on-and-off for the rest of the day. Considered signing up for another testing day when I got home but the thought having to put myself through that again turned me off of the idea. Ended up getting a 39 (12, 12, 15). I must have gotten really lucky in that all of the parts I found really difficult were all experimental.
tl;dr Do not use how you feel after your MCAT as an indicator of your score.