No, your brain is 100% ok (at least as far as I can tell from here haha).
It's just the lying, you know.
Lying to yourself. Lying to yourself about your work. Lying to yourself about what meaning to your life your work has.
Committing to a project does not make your guts loving doing the works.
Of course I don't really know if you are being honest to yourself or not. It's just an educated guess based on my own experiences (and those of others I witnessed).
How realistic are your expectations about your work (and life)? How hard are you on yourself (and others)?
Or maybe you are just afraid to loose your spontaneity (that you value) and become a control-freak, if you do full GTD?
Did you know that GTD makes you more spontaneous because you get clarity about what you are NOT doing?
Or are you afraid of what happens when you actually complete one or the other of those projects? Fear of success? Fear of failure?
Practical tip: Maybe you want to just put most of these projects on someday / maybe and tackle just 1-2 of them for starters.