Reddit mentions of An Introduction to Medicinal Chemistry

Based on your post, I think you need more knowledge of biology and chemistry before you can really approach pharmacology. Gotta walk before you can run, if you will. But you're taking organic this year and hopefully biochem and a biology class next year so that will come with time.

If you're really excited about PK though, check out this youtube primer on the subject (~30min total). I also suggest checking out Derek Lowe's blog (/u/dblowe) In the Pipeline. There are over a decade of posts and especially since it's become associated with Science Translational Medicine, he does a great job introducing topics for those not directly in the field. He's made 73 posts tagged PK, and it may also give you insight about what your future career will be like and controversies in medicinal chemistry.

My undergrad med chem professor sadly passed away shortly before the course began, so I bought Richard Silverman's "The Organic Chemistry of Drug Design and Drug Action." Amazon has the 2nd edition (the one I have) for $13 and you may enjoy flipping through it when you take organic. However, it's a pretty advanced book (probably for folks who have already taken a med chem class) so you can also consider the legend EJ Corey's short book "Molecules and Medicine" or Patrick (the standard med chem textbook) if you want to see medicinal applications of organic while you take the course.

I use An Introduction to Medicinal Chemistry by Patrick Graham when I teach my Medicinal Chemistry course. https://www.amazon.com/gp/offer-listing/0199697396

There's also a good free online EdX Med Chem course you could check out. https://www.edx.org/course/medicinal-chemistry-molecular-basis-drug-davidsonx-d001x-2