I wanted to wait a while before responding, because advice in the heat of the moment (right after you got your score back) can be irrational and based too much on emotions. Hopefully you've had enough time to cool down.
Thankfully there were some amazing replies from multiple posters (Goro, Go Wemby Go, and gyngyn are guaranteed to give you gold). I'm hopeful that you took some time to regroup and evaluate everything, especially your timeline. The biggest thing that happened with your score was a shift in your timeline for applying to medical school. That's huge in the short term, but in the big picture is a blip on your life's path.
Before you do anything else, write down everything you recall from your exam. I don't mean questions and passages, but the little things. How was your focus, your stress, your anxiety level, and your immediate response to weird questions? What surprised you on the exam and about the exam? How much of a factor did you not being the best test-taking version of yourself that day affect your score? After you assess that, ask yourself if there were subjects you didn't know, questions that made no sense, or tables/graphs/charts that overwhelmed you. This is essential, because it will dictate whether you focus on content (content is very rarely the issue when someone scores >500 but more than 10 points below what they expected) or on test taking.
I have seen many (and by many, I mean a few hundred) people raise their score from around 500 (24 back in the day) to 510 or higher (31 back in the day). In nearly every instance, it came down to looking at AAMC questions differently. It came down to worrying less about the content of a passage and more about the trends and the fundamental information buried in their tables and figures. It came down to learning the art of taking an AAMC exam. I found that when a student discovered a new way to solve a problem, they were less susceptible to making a careless mistake. When they developed confidence in their revised approach, they were able to work through material more quickly and without wasting time second-guessing themselves. You need to get to that point mentally.
This next time preparing, you need to focus on test skills and how to approach AAMC materials. Try questions from multiple resources and see if your techniques work on all of them. If they work on everything you try, then you will walk in more prepared.
As far as what to study, I have my strong opinions of what is the most helpful and what is ineffective. I refrain from sharing my exact thoughts, because they go against the grain for the most part. I will say generically, a different resource is best for each of the four subtests on the MCAT. To be best prepared, you will will find company X is best for CARS, company Y is best for PS, company Z is best for CP, and company Q is best for BB. Some of these items are even free.
Most importantly, do AAMC materials again. Do them more than once. Take FLs a second time. Do their SBs a second and third time. The score is so unimportant; it's about exposure to the style and recognizing their nuances. It's like watching a movie a few times, where you see something you didn't notice before and you ultimately get a better understanding of the movie.
You will be fine in time. Getting that score back no doubt sucked and left a cerebral scar for life. Guess what... you'll meet several people in medical school with the same scar. One night after power studying, you'll compare battle scars and laugh about them.
Good luck!