I wish you the best!
First off, congratulations on pre-med! It's not an easy field and requires a lot of hard work, but you're on the right path by reaching out!
I'm happy to share a few tips which will hopefully help:
1. As counter-intuitive as it may sound, taking mini breaks actually helps refocus the mind. If you incorporate "mini breaks" into your studying, this will help with your concentration, comprehension and retention. Studies have actually shown that working in 45 minute sprints and taking a 15 minute break, helps in these areas. Consider studying for a few hours, taking 15 minute breaks in-between. Then take a longer break for lunch, maybe 30 or 60 minutes. Walk outside, move around and get blood flowing, which also helps with renewing your focus to go back to studying.
2. Study in a variety of ways: oral conversations, flashcards, using different colored pens/highlighters can also impact your retention of difficult information. From experience, I've come to realize that I learn well with the colors orange and blue (not just because I'm a Broncos fan!) but my memory works best with these colors. Try it, see if you notice a different in your learning style!
3. You mentioned foregoing sleep, and while difficult to squeeze in given your focus area, it's another important factor in allowing your brain to reset so it can recover and start fresh the next day. I've added a few resources below for you to check out; hopefully they help you.
Best of luck!
Gabby recommends the following next steps:
1. Engage in a Mindfulness Activity.
2. Collaborate with Motivated Individuals, if feasible. Perhaps a roommate.
3. Anticipate a Reward for Yourself.
4. Eliminate Distractions from Your Surroundings.
5. Accomplish Your 'Recharge Routine.'
6. Participate in Physical Exercise.
7. Enjoy a Brief Rest.