Here's a step by step of what I'd recommend you read, starting from nothing.
Step 1: Learning the Basics
This is the most popular introductory economics book in the U.S. (for A.P. high school students). It provides a strong intuitive explanation of macro and microeconomics. Requiring very little math and full of lots of attractive graphs/pictures, this book is perfect for anyone who wants a strong grasp of basic economics. The best part is that each chapter (usually only a mere 20 pages) is easy and fun to read.
McConnell's, Brue's, Flynn 18th edition
Step 2: Intermediate
If you want to progress beyond introductory economics then you'll start getting into the quasi-"real" (college) stuff. This is where microeconomics and macroeconomics divorce. Unfortunately for the layperson studying on his own, the quasi-"real" stuff requires a lot of math. Calculus I and II are absolutely required. Calculus III (partial derivatives) may or may not be needed (though it will be needed later).
The standard macroeconomics textbook, Mankiw's Macroeconomics 8th edition does a really good job of expanding upon the basic macro models you've already learned and doing so in a sort-of-quantitative way. With this textbook you'll go beyond just knowing general concepts. You won't be a full fledged economists just yet, but you'll be well on your way.
Macroeconomics: 9781429240024: Economics Books @ Amazon.com
The best intermediate microeconomics textbook ever, Varian's Intermediate Microeconomics: A Modern Approach (also 8th edition) is really good. It not only matches Mcconnell Brue Flynn's introductory textbook for clarity, it does so in a very mathematically heavy way. This is important since economics (but microeconomics in particular) get very math-heavy from here on out. Still, this textbook is a pretty big departure from your introductory one; soon after you pick it up, you'll learn how little you previously knew.
Intermediate Microeconomics: A Modern Approach (Eighth Edition): 9780393934243: Economics Books @ Amazon.com
At this point you're in good shape. You're pretty much done with general economics for college. Everything after this point will require a lot of math (seriously it will read like a physics textbook). If you don't know Calculus III, you'll need to learn it. Still, if you're not deterred, I urge you to continue. What's next will significantly expand your technical understanding beyond just simplified, short-term models. Beware, this is all graduate level material.
Step 3: Advanced
David Romer's Advanced Macroeconomics is considered to be the book of Macroeconomics; it's the "bible" of most 1st year graduate school macroeconomics classes. It's really quantitative. While Romer does a good job of intuitively explaining the manipulation he does, if you can't follow the math, don't bother reading. However, if you can, you'll love it. It covers material that was almost entirely untouched thus far. The first third takes a longer approach on growth models, the second third focuses on the business cycle, pricing, and new-Keynesian attempts to explain it all, and the last third focuses on each component of GDP in depth.
Advanced Macroeconomics: 9780072877304: Economics Books @ Amazon.com
This book (which I have not yet read) is supposedly the equivalent to Romer's Advanced Macroeconomics but for Microeconomics. While I cannot give much personal advice/analysis, I expect this book to be incredibly math-heavy (microeconomics is perhaps even more math intensive than macroeconomics) and to delve deeply into the nitty-gritty of individual optimization, choice theory, game theory, and risk. I'm very excited to get started.
Advanced Microeconomic Theory (3rd Edition): 9780273731917: Economics Books @ Amazon.com
If you manage to read and understand all five texts, you will effectively "understand" almost all important work in economics. Basically, you'll be able to answer every question on Quora relating to the subject. :)
In all seriousness, economics is absolutely awesome and essential to explaining how society functions, how politicians are stupid, and how complicated the $77,000,000,000,000.00 World Economy really is. It's an incredibly worthwhile subject to learn and I wish you the best of luck in your endeavor.