WordPress header.php/menu problem (please help)

I’m using WordPress to create a portfoio site. I can’t seem to get the links working correctly in my header.php — I’ve got a menu on my front page with links to: About, Resume, Work, and Blog. When I click on any menu link from the home page, it takes me to the correct page: https://www.mysite.com/wordpress/about/, but then the header menu doesn’t work after that. It repeats the directory:
https://www.mysite.com/wordpress/about/about/

I’m using a new template for each page (about.php, work.php, resume.php, blog.php) and each page inserts the same header.php

Please help….