Don't you think it is a bit premature to consider putting her down? Did you discuss her symptoms with the vet over the phone and they told you it could be something terrible? Personally, I wouldn't even think of such a thing, even if the tail had to be amputated...
If it is anxiety, and suddenly eating books and things sounds like it to me, you could try prozac...I am not a fan of such things, but it is better then death. Certainly she deserves a chance to get better...a decision that big should not be made in one day. If you can't tolerate destructive behavior, find a way to confine her..maybe in the kitchen. (Remove chairs or anything she could chew on and give her some kind of bedding.)
I hope someone at Curezone intervens and gives you more advise then I can right now.
Please let me know that the vet says. Get a diagnosis and then get some holistic help.