Yikes! Help I was uploading stuff and overwrote some file? and now when I try to submit a comment on the contact form I get this message:

"Warning: Cannot modify header information - headers already sent by (output started at /home2/tehoenet/public_html/shop/includes/extra_cart_actions/wishlist_cart_actions.php:11) in /home2/tehoenet/public_html/shop/includes/functions/functions_general.php on line 44"

and when I try hit the add to cart button, I get the same message. I looked at line 44, and it just says "header('Location: ' . $url);" so I don't know what's going on.