wp 3.5 Admin user not working – redirecting to profile.php

All of a sudden (no recent changes), my blog’s admin user can no longer access the admin dashboard.

The login is successful, but it just automatically redirects to /wp-admin/profile.php (and gives the insufficient permissions error on that page)

When I try to manually go to /wp-admin it says “You do not have sufficient permissions to access this page.”

I tried disabling all plugins and the same error comes up. I tried using the default wp theme, but the same error comes up.

When I check the main admin user in phpmyadmin, it seems to have all the correct permissions (level 10, admin rights, etc)

Any ideas?