Reddit reviews The Guitarist's Music Theory Book - with Audio CD

If you were taught by learning tabs, then you most likely were taught how to play songs and not how to play and understand the guitar.

You need an instructor who will teach you how to learn music through using the guitar. Sounds like you missed out on some basic concepts of theory, too. You could always get a music theory book, such as The Guitarist's Music Theory Book

This stuff was all really confusing to me for months. Believe it or not, it's actually way easier than it all sounds. I see most people have kindly written out some detailed explanations, but what I would personally recommend is just about any music theory focused on the guitar itself.

Music theory in general is a huge, huge concept so many books will be overwhelming to most.. but for just guitar you can find a lot of good books. Once you get just the guitar theory part down.. THEN you can move onto serious music theory or at least that is how I did it. It was way easier to understand after.

This is the one I started with for guitar:
https://www.amazon.com/Guitarists-Music-Theory-Book-Useful/dp/1893907783

It's really short but you can study it for quite a while and it has lots of great audio tracks along with a very simple approach. It doesn't go into complicated rhythm or notation.. just a simple ground approach to guitar theory. It cleared up a ton of smoke for me and all of a sudden I actually understood how the hell to move around the guitar neck.