Changed Site URL and Lost Access

I had changed my Site URL in www.remarpro.com and lost access to my account, editing pages, everything and have no idea how to go back or get into it any longer. (from https://www.Merridethhawkstudio.com to https://www.merridethhawk.com)

I am a complete beginner, on an older forum it discussed FTP and/or wp-config.php, but I have NO clue what any of that means or how to do it.

Any detailed directions or help would be GREATLY appreciated!

The page I need help with: [log in to see the link]