I'm the same way...I just get so "in" to what I read...if it's good. And the LOTR is Goooooodddd!
Really, my husband is quite indulgent and will listen to me read and read, unless he's laying down and "is overcome with weariness".
Being able to get really into a book is almost required growing up with a big family. I get to the point where people can be shouting at me and I don't notice them. Though there's a definite downside to that, too...
I'm a little worried about this novel project as that's going to be even MORE consuming than just reading. I've always made up stories in my head in order to amuse myself, and would sometimes find myself whispering conversations out loud. Hmm...how to freak out your co-workers?