Why can't I log into iMessage on iOS 6.1?

I still have iOS 6.1 on my iPod 4 and I've been using iMessage for approximately a year now without any problems, so this is my first (and hopefully only).

Whenever I go on the "iMessage" app, it sends me to the beginning iMessage page (the one where you "Get Started") even though I've already done this when I went on iMessage the very first time. I followed the iMessage account setup thingy, where you enter your Apple ID and password. After that page, it sent me to the page where it asks me if I would like to be known as "______@hotmail.com" and I tapped "Next". It makes me wait for a while before going back to the iMessage account setup (where I enter my Apple ID and password). I tried repeating the account setup but it just keeps on sending me back.

Also, whenever I go to Settings ----> Messages, it sends me back to the Account setup page. What do I do?