If you cleared your cookies then that would explain why you can't access the login page because that is how the feature works.
To get back to your login page is easy if you can remember the secret word you chose when you saved your settings. Simply add your secret word string to your site's URL as follows:
This should get you back to your login page.
If that doesn't work (or you can't remember your secret word),
FTP your .htaccess file to your computer and then delete the code between (and including) the following tags:
Then save the file and FTP it back to your host.
Alternatively, you can look for the ".htaccess.backup" file in your site's root directory using your FTP client and rename this to ".htaccess" after deleting the active version.