Possibly an easy fix. Turn off steam, ctrl+alt+del to ensure its off. After its off, go to your steam folder and delete the clientregistry.blob file. Its something like that, if it isn't named that exactly. After you delete this, run steam and then you will log back in. It will clean out anything on your end and it resyncs. Try that.
Doesn't work, the issue is on steams end.
I'll copy and paste one of the replys they sent me (it got me no further and has now started a endless download starting loop).
Thank you for contacting Steam Support.
Please exit Steam and go to the folder called C:\Program Files\Steam\ (this is the default location for a Steam installation - if you set a different installation directory, you will need to browse to it).
Delete all of the files in this folder except:
The Steamapps folder and Steam.exe (If 'exe' is not visible, look for the black and white Steam icon)
Restart your computer.
Then, you will need to launch Steam.exe from within the Steam installation folder, and not from a pre-existing shortcut.
With Steam running, re-test the original issue.
Note: This process will not affect your currently installed games.
If the issue persists, view the following article for further troubleshooting:
Title: Troubleshooting Network Connectivity
Link: http://support.steampowered.com/kb_article.php?ref=1456-EUDN-2493
If you have any further questions, please let us know.
I have managed to find a workaround that relies on luck (I have pulled it off 4 out 5 trys), will let you play the game but you aren't authenticated and won't have your preorder goodies.