Can't Log in

Okay, try signing out of iTunes, now sign back in... It may not work at first but after a few trys it should. Now, look in the top right hand corner where the amount of money that you usually have is (if you use prepaid cards). NOTHING'S there. Why!? This happened to me and then I called some friends and asked them and they're having the same problem. What's going on? I have about $15 in my account.