Can't access admin panel. Moved WordPress&Site URL files..cannot find.

I don’t know how to fix a huge mistake I made. I am suppose to GO LIVE tomorrow (Tuesday), but because of the mistake, I cannot access my WP Admin panel, and I cannot launch the new site as planned.

I built a new site under a WordPress blog (while keeping the old site up and running) on a Yahoo host. I was trying to move the blog site to be my main/root site for the go live, but made a huge mistake.

Under the blog’s General Settings, I changed the WordPress URL to the default address listed: “http://domain.com/” . I also simultaneously changed the SITE URL to the same default address listed: “http://domain.com/”.

I hit save, and of course, lost access to the WP admin panel. When I did this mistake, I did not set a new file folder name or subdirectory name, so in reality, I have no idea where these files went. I thought perhaps they were moved to the ROOT file, but checked in Yahoo’s File Manager, and the wp-admin files are still showing as a subdirectory of the BLOG file. The Blog file is still showing as a subdirectory of the ROOT file. So, I don’t know what happened.

I believe the both the SITE & WORDPRESS URLs were automatically defaulted by Yahoo to a “http//domain.com/blog” subdirectory when I first activated WordPress into my Yahoo server account.

I researched everywhere. All directions say NOT to do this (unless you know what you are doing) but there are no instructions on how to FIX this situation once the deed has been done.

In trying to salvage the damage, I clicked on Yahoo’s Blog Manager ‘fix’ offering to automatically go in redirect the links after changing the word admin files; but this did not work either.

I’m at a loss in how to fix this. I’ve tried everything for 2 hours now. Thank you for any advice or guidance!

(Think I am still on the WordPress 3.2.1)