@HappEness I am sorry to hear about the struggles you are facing. I don't want to tell you to lower your goals, because everyone has dreams and I want you to be able to achieve yours. However, the cream of the crop of people are entering this profession. There will always be someone that has higher grades or test scores than you and there is no shame in that. Getting into any medical school in the United States is a massive accomplishment. A 510 is in the 80th percentile, which means you're scoring better than 80% of the students that take this exam and these are some of the smartest people in the country.
Your science sections are stellar and show that you have more or less mastered the content and passage strategy for these sections. CARS is where you could use some more work. You need to reevaluate your strategy and see why you're making mistakes despite using the strategy. You need to look into why you're missing questions in the first place. Are you not understanding the passage well enough? Are you spending too much time reading and not having enough time to properly answer the questions? You need to start pinpointing what your issues are. This is a bit harder for CARS than the science sections, which tend to be a little more concrete in what you're missing. You need to develop a strategy around the mistakes you're making.
So, if your issue is that you're spending too much time on the passage, then a strategy you can start implementing is holding yourself to only 4 minutes per passage and seeing if that helps you work better. If not, then keep tweaking that until you find a balance between reading the passage and answering the question. Pinpoint exactly where your issues are coming from and then start developing and tweaking strategies to overcome these issues. If you know what your issues are and need advice on developing some strategies, please reach out and I would love to help you.
I really empathize with your situation. It's hard feeling inadequate. It's hard feeling like all of your peers are progressing while you're still running in place. I want to say though that what you have accomplished so far is nothing to be disappointed about. You clearly care a lot about doing well and I would love to help you achieve that goal. So, please reach out to me with any specific questions and i'll definitely do my best to help you. Also, try your best not to get discouraged. Success on the MCAT is definitely part a mental battle and I truly believe that staying positive can add a few points on test day. Keep up the good work and please reach out with any further questions!