Help with Book title?

Hey all! I was wondering if anyone would be able to help me find a book I read like 10 years ago. It was a YA book that took place in a semi post apocalyptic world, where there was a fairy world and the human and fairy worlds were in a war and it took place after. A part of the book has the girl protagonist going through the ravaged and empty fairy world, which earth had nuclear bombed. I've been trying to find it but no luck! I think it had a one word title like Shimmer or Gossamer (not either of these books though)