I pre-ordered Katy Perry's new album Prism and it won't let me download it!

Help!!! I pre-ordered katy perry's new album, Prism and when i go to ituned it says i purchased them, but its not under my purchased tab. It released on 10/22/13 so the album is out. The link on the email they sent me just goes to the home page. How do I download it? (the only apple device i own is an ipod 4g)