Andrew,
You are not yet experiencing "study fatigue." I believe you're questioning the worth of the endeavor; determining if the "juice is worth the squeeze" using the popular phrase. At two weeks into to a six-or-so month process, it sounds to me as though you're re-thinking the value of the PMP. Unfortunately only you can determine the value.
My motivation for achievement has always come from within.
Studying for the PMP exam is difficult and can be a psychological downer. For me it required a lot of mental toughness. It was like learning to be fluent in a foreign language in 5-6 months ,or worse, the words are English but they don't mean what you think they mean.
You may find that having a written plan and executing on that plan will help. Preparing for the exam will take time away from the things you believe you'd rather be doing or time away from family. It's a commitment. You will not be able to half-bake this cake and expect to be successful.
Good luck.