That's weird. Try the normal things first.
Check your network connection. Well, it's probably okay, but check it anyway.
Stop and restart iTunes.
Log out of your account and log in again. Start iTunes.
Shut down your machine. Boot it, and start iTunes.
It looks as if somehow it got confused and stopped connecting to iTunes. It obviously saw some of the data from the iTunes server.
If none of that works, try it all again in an hour or so. It may be an issue with an iTunes server. I wouldn't try reistalling anything on your machine yet. Patience may be your best bet for now. (Btw, iTunes is working fine for me. I can connect to the store and everything displays.)
Hope this helps! Good luck.