Jason, what you're describing hit me at about the same time. (I'm about to do the oncology coding exercise for Module 1 Section 18 right now.) I would say try not to panic. The coding handbook is a reference that you will refer to always. I work in the coding department of a hospital system currently, but not as a coder. I can tell you that at our monthly staff meetings items from the coding handbook are reviewed and discussed for a review for the staff. So, even experienced coders still need it and use it. You want to read through it, make some highlights where it's helpful and get the lay of the land, so to speak. But it's more like a reference guide that you'll keep circling back to and using as needed.
There is so much terminology to learn, isn't there? When I'm feeling overwhelmed, I try to focus on studying and reviewing the things that will probably help me the most on the fly, in the future. Major body systems, major parts of those systems, and any body parts/diseases/treatments that I know I'll never remember belong to those major categories. For example, if you already know a lot about cancer or gastro just due to life, that's great. You might need to spend more time covering urology instead. Work on your weakest area when you sit down to review. Another thing I focus on are the boxes in the chapters with sound-alike words. I know that I want to get those down so that I don't make too many really embarrassing mistakes on the job, like confusing ileum with ilium.
Another thing I'm doing is taking notes over and reviewing the coding conventions and the guidelines at the beginning of each chapter in the ICD-10-CM. As great as it is to immediately recall where the calcaneus bone is, it's going to be really important to know what the square brackets mean [ ] when we're looking up codes, right? It sounds like you're doing great. Focus on the big picture and try not to get too overwhelmed. You've got months and months of studying ahead to cement all this in your mind. Remember, you know that you can do this, because other people have gone before you and they've done it! So, you can do it, too!