All links broken after changing permalinks to /%postname%/

My site was working great. I then added categories, changed my permalink structure to /%categoryname%/%postname%/ – it worked fine. Then changed it back to /%postname%/ and now everything is broken. Default is the only format that works.

I’ve read countless forums and have tried all of the following with no luck at all:

1. Deactived and reactivated all plugins
2. Deleted htaccess
3. Switched theme to Twenty Fourteen
4. Changed htaccess permission to 666

Currently, my htaccess file has the correct code:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

I’ve been having this problem for hours and my entire site besides homepage is broken. I don’t know if this is a database issue or what, but I am out of solutions and am very frustrated. Any help is appreciated.

Thanks