The Bible: Should we take it to the exact letter?

I am not an expert on religion, but I remember being in sunday school with my sister, and she was kicked out of it for saying, “I don’t Believe in Cannibalism.” When we learned that people ate the flesh of christ, and drank his blood (Not sure what the full story was…). My family drifted away from church-going-stuff when we moved to Europe, but now that we are back in the U.S., I feel like so many people are taking the bible too seriously, and I have to ask:
Is the bible a sort of, “story-book” that dumbs down what really happened, or should it be taken to following everything it says. I mean, I don’t have a problem with gay people, but so many people take the bible to the extreme. Hasn’t it been rewritten, parts taken out and changed by priests that didn’t agree with it? How can people be sure that it isn’t playing like “telephone”, where the message is changed the longer it goes on? I’m sorry if this is too long or something, but it really bugs me sometimes. xD