Help – Can't get back to mysite.com/wp-admin!

I just messed something up. I was trying to change my landing page to my Home page, and thought I’d add “home” to the URL on one of the Admin pages (can’t remember which one – argh). So now I get a 404 message saying the page doesn’t exist when I try to enter my site.

Old: https://www.artisangardening.com/wp-admin – Used to work, but I didn’t like the landing page…then I accidentally messed things up
New: Automatically changes to https://www.artisangardening.com/home/wp-admin – Gives me a 404 message, and I can’t go anywhere, even back to change things back

Please help. Thanks.