Have your .htaccess like this:
RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteRule ^ http://www.mysite.net%{REQUEST_URI} [L,R=301,NE]
RewriteCond %{HTTPS} on [OR]
RewriteCond %{HTTP:X-Forwarded-Proto} https [OR]
RewriteCond %{SERVER_PORT} ^443$
RewriteRule ^ http://%{HTTP_HOST}%{REQUEST_URI} [L,R=301,NE]
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://(www\.)?mysite.net/.*$ [NC]
RewriteRule \.(gif|jpg|png|tif|js|css|xls|xlsx|zip|rar|pdf|ods|ots)$ - [F,NC]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-l
RewriteRule ^(.+)$ index.php/$1 [L]