Don't feel bad for not coding. The truth is, this industry can make people feel really bad for not coding constantly. The mantras of "Get Sh*t Done", "Great Artists Ship", "Always Be Coding", "Hack your life", "If you're not coding your competition is" and many other lousy, empty and ultimately meaningless statements just serve to make anyone who's not constantly coding feel like something is wrong with them.

Chances are you're like most people and have a wide variety of interests and hobbies, and so trying to keep up the pretense that you just care about your startup or current project can be emotionally exhausting. It's basically lying to yourself.

I don't really have a concrete answer for you in how to break this funk. Funks can happen. The advice all people here have given you is spot on, I will just add that all that advice should be tried and discarded if not useful, it's what worked for them, might not work for you. I personally also suggest include avoiding online content and getting outside. I also suggest you figure out some way to learn to make peace with tedious work, it happens in almost all client work.

Good luck friend!