Oops. Changed setting and now all admin pages redirect incorrectly

Ok so among my many other problems, I’ve also just majorly messed something up.

I went into the settings area and changed the wordpress address to https://www.domain.com/index.php so of course now all of the pages in my admin area are redirecting to https://www.domain.com/index.php/wp-admin/etc

I can’t get back to the setting page (or any other admin page) because it keeps redirecting to the nonexistent path.

Which file is telling it to redirect? I need to d/l it and edit so it’s no longer redirecting. Can someone help?

thanks!