Changing URL names

I changed the URL name in the “WordPress address (URL)” and “Site address (URL)” from “https://www.oguindc.com/blog” to my new domain name which is “chiropractorkirkwood.com/blog” Now I can’t log in with my regular username and password. When I try to log in it redirects me to

https://chiropractorkirkwood.com/blog/wp-login.php?redirect_to=https://www.oguindc.com/blog/wp-admin/

saying the page isn’t found. I don’t what to do here this blog is extremely important to my company. Is this fixable? Really I just need the files on the blog so I can move them to my new URL blog. What do I do?