It' basically the Dunning-Krugger curve - you're well enough into the last part of it so you are well aware of how much there is to learn about it and how you will never know all of it, thus you don't have and never will have the same kind of cocksure belief that "I know this shit" as somebody who knows just a bit but not yet enough to understand how much there is to know.

It's all perfectly normal, IMHO.