Organic Chemistry as a Second Language: here
This book helped me a lot in undergrad. I TAed and tutored organic for many years and I always recommended this book as a way of understanding rather than memorizing. They will develop some good chemical intuition with this imo.
No matter what your actual textbook is, I highly recommend Ochem as a Second Language by Klein Organic Chemistry As a Second Language, 3e: First Semester Topics https://www.amazon.com/dp/111801040X/ref=cm_sw_r_cp_api_i_v4ajFbPZ9ZWHZ. This is the one I used several years ago, not sure if the newer editions are worth it.
Organic Chemistry As a Second Language by David Klein
Buy both the books!
Instead of using my class textbook, I used these two books. These books will cover most of what you need to know in your ochem courses. I wasted money buying the class textbook when I could have used these two books alone.
I'd start with getting a good understanding of anatomy/physiology, microbiology, and just biology in general, and then applying basic organic chemistry to the mix. You really need to understand a lot of the concepts (maybe not mechanisms) and processes of all of these general studies to really comprehend biochem aside from just memorizing it. As far as a single book to explain that to you without that basic knowledge, that is hard. But texts books are certainly a start. Organic Chemistry as a Second Language is a great one for really understanding orgo. Many props to you for trying to get ahead of the game and looking into this stuff in high school.
Definitely purchase this book! Professor Klein taught at my university, and my orgo II professor was his mentor as an undergrad. This is hands down the best book to learn organic chemistry in an intuitive way. People have been swearing by his textbook ever since he started teaching orgo 15 or so years ago. DO IT!
So many textbooks we are assigned in undergrad are utter crap and written for a second or third pass through the material - not a first time exposure. You still have time to recover your grade.
Edit: http://www.amazon.com/Organic-Chemistry-As-Second-Language/dp/111801040X
You might find inorganic is more to your taste. Or you might like analytical chemistry is more fun. There is a lot that you'll see in the next semester that will make the stuff from this one just click better.
Over winter break get your paws on Organic Chemistry as a Second Language and Pushing Electrons and let those help you with the stuff you aren't solid on yet. Then do problems until you are heartily sick of them and you will absolutely ace the ACS exam at the end of Ochem 2.
I purchased Organic Chemistry as a Second Language and it was really helpful for chemistry. I have an copy that I am selling if you are interested.
I've been fortunate enough to have a couple of really great Orgo professors that have been able to convey the material in a way that was comprehensive rather than just pile of crap to memorize and organize. However an amazing resource I used was "Organic Chemistry as a Second Language." This book was seriously one of the key factors in me receiving a B in Orgo 1 and an A in Orgo 2. These are amazing for anyone who is taking the course and also for review of topics for the MCAT. Has tons of simple explanations and extra problems. There is a book for first semester topics and one for second semester topics; however, depending on how your professor teaches the material, you may just want to get both at the same time. Here are some links:
It's a tough course, but keep your head up, power through, and kill that final!
http://www.amazon.com/Organic-Chemistry-As-Second-Language/dp/111801040X
You were able to academic flourish in a terrible high school. Out of all the applicants who applied to that university, you got accepted. You are taking multi variable cal/cal 3 and organic chemistry in your first year when other first year students are only taking calculus 1 and general chemistry. Whatever the reasons why your friend are having difficulties in their university studies are independent of your own academic abilities in university
It is fine that you have a little anxieties about university, but the reasons above, I believe, are why you should feel academic prepared for the challenges in your university life.
Is multi variable calc and organic chemistry your main "difficulty" course for the fall? If so, you should be fine but make sure to brush up on your math as multi variable calc builds on the materials from pre-cal to calc 2 (but that rather obvious for mathematics). Ochem might be a little trickle as it is the subject where some student love or despise it. If you have some spare cash around, think of purchasing Klein's "Organic Chemistry as a 2nd language" handbook as most students have it helpful--I did.
You got this :)
EDIT: Studying in college is a little different than in high school, so the website, studyhacks by Calnewport, can provide a lot of helpful studying tips for you, among other things Newport writes on there. Newport also has his stuff written in books, if you prefer a physical medium.