yeah, i used to have those same voices. like gretchen said, the more you learn about their past and methodology, the smaller the voices will get. i'm at the point where even if i desperately wanted to go back, there's NO WAY that i could convince myself that they have the one tru religion.
if you haven't read CoC, do that. for what it's worth, it may be worthwhile to examine the history of the bible and christianity in general too. this helped me immensely because i think some of us are left with that "what if they're right" feeling because we are now left with a strict fundamentalist viewpoint on the bible (i.e. inerrancy). if you see their foundation for what it is, the entire JW belief structure comes crashing down as the fable it is.