Accessing Source Files

It is very difficult to help with this type of problem without a link to your site. Please post a link where the problem can be seen and someone might be able to help.

The problem is probably in the code that generates the menu, usually in header.php. It is likely just after the code that creates the link for the Home page.

Please put your header.php file in a pastebin and post a link to it here.

EDIT: It could be coming from a filter on the menu. That could be set in functions.php, or in a plugin.