infinite loop on wordpress install? because of site.com\wp and not www.site.com?

I just installed WP on my site using cpanel…

The blog would not appear, as it claims an infinite loop because I have these lines in my .htaccess file:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^derekbeck\.com [NC]
RewriteRule ^(.*)$ https://www.derekbeck.com/$1 [R=301,L]

which forces all pages to go from derekbeck.com to https://www.derekbeck.com, yet WP apparently requires it not have the www. at the beginning, and thus an infite loop, with the blog not coming up, and I not being able to login in to the admin section either.

How do i get around this? How do force the blog at https://www.derekbeck.com\blog and not derekbeck.com\blog?

Thanks for your help!
Derek