A couple of thoughts. One, there's a ton of work that doesn't need databases, or operating system knowledge. It helps, but its not essential. Android developers are hot hot hot right now, and its not a huge system to learn (I'm a mobile dev manager).

As mentioned before me, you can learn a lot on the job. One of the best dev's I know never finished college either.

I am always looking up the proper syntax of commands (find -exec anyone?) It just takes repetition and the constant thought that "maybe there's a command that does this better".

Finally, put down the math books. Put down the compiler books. Data structures and algorithms, sure, but those others. Bah! Now, if you want a supplementary book that helps a ton, pick up a patterns book, preferably the "Gang of Four" book (http://en.wikipedia.org/wiki/Design_Patterns). It helped me to look at problems in a bit more of a formal sense, and it allows me to say "Oh this is such and such a pattern" and other devs get it immediately.

Don't get discouraged. You may just need a new job where you are mentored if you feel like your skills and experience is meaningless. Your desire to learn and your passion for your chosen career make you a fertile ground for training.

Good Luck!