wordpress/woocommerce site repair, redirect loop & giving admin access freely

My site for a few days has given anyone who visits it admin access. Further, while trying to set it up to only work with https:// links so SSL EV certificate would show green lock in the browser on all pages, I changed the URL to [login to view URL] for the site from [login to view URL] for the site in general preferences. Since then it goes into infinite redirect loop attempting to visit wp-admin page. I need the site to always be in https:// so that they see green lock in their browser, and also need backend to work and not give everyone admin access.