Try logging out from the site and logging back in. If you can't log out you'll need to empty your cookies:
In your internet browser, go to the drop down menu marked; “Tools”. At the bottom of the “Tools” menu, click on “Internet Options”. A window will pop up with different tabs at the top to change your internet options. The first one you see is marked “General”, with a section called “Temporary Internet Files”, click the button there marked “Delete Cookies”.