I did fine; again, I think my chronic fear is the whole visual aspect. When reading, whenever they referred to the possessed Regan as "the demon" or "it" speaking, I never pictured the face; in fact, I don't even picture the voice. I only take the line of dialogue as spoken in fury, and that's that.
As a stand alone book, it's pretty compelling. I found myself actually intrigued in some of the factual aspects, as the book went in depth into explaining certain mental illnesses and psychoanalysis (that, because for the majority of the possession in the book, most characters remain convinced of erratic psychological behaviour, schizophrenia and multiple personalities - never a demon, until towards the end, and even then it isn't explicitly said that it was supernatural). Aspects of Black Masses and "case reports" of exorcisms (fictitious? Perhaps) were interesting, if not mostly disturbing.
To be honest, I half expected myself to throw the book at the wall, but that never came to be. Sure, when reading alone (if I could help it, in daylight), I'd get unnerved at the noises my house makes, or tricks the light plays on my peripheral vision. Again, the description of the plot didn't bother me; the visual undoubtedly will.
I can honestly say I'm proud I was able to get through the book, although I'm perhaps a tad more disturbed by the darkness. But that's probably just because it's still fresh on my mind.
And maybe, because due to my own sheer STUPIDITY, I decided to research the actors of the movie to see if my images of the characters were close (I didn't check Linda Blair), but with some, the Google image result brought up pictures of the Face. I did my best to exit the windows. We'll see how it effects me tonight.
EDIT: The lights just flickered when I published, the book still beside me. Mom, if I start speaking Latin or if my head does a 180 tonight, call the priest immediately. No months-of-doubt shit like from the book. It's a freaking demon.
BONUS EDIT: I can't stand to be in the presence of the book. Yeah, yeah. Dramatic. I'm truly not kidding. Back when I bought it, I was electrically compelled to reading it immediately; now, I'm unnerved at the thought of it being across from my bed on the bookshelf as I sleep. I know it sounds stupid; I also know I said I wasn't OVERLY scared by it, but I think it's all psychological. The type of thought where it's like, Hey, Matt, across from you is the image that scares you so much, but in text. I think I'm going to toss it.