aprilcartergrant, have you backed everything up? Also, what I usually do after getting a new blog up and running is, I download a copy of all the files including the wp-config.php file to the harddrive.
And then if something goes wrong, I'd just upload that file that might have been screwed up. Like Viper007Bond said, as long as your DB connection settings in the wp-config.php file is right..you should have that existing data there and showing up.. =)
That happened to me before, I accidently uploaded the wrong wp-config.php file into the wrong directory and it was screwy, but then reuploaded the proper one that I had originally had, and it was ok. So, maybe something isn't quite right in that wp-config.php file. :/
// ** MySQL settings ** //
//Added by WP-Cache Manager
define('DB_NAME', 'TheOneYouHaveForThisBlog'); // The name of the database
define('DB_USER', 'TheOneYouHaveForThisBlog'); // Your MySQL username
define('DB_PASSWORD', 'TheOneYouHaveForThisBlog'); // ...and password
define('DB_HOST', 'localhost'); // 99% chance you won't need to change this value
// Change the prefix if you want to have multiple blogs in a single database.
$table_prefix = 'wp_'; // example: 'wp_' or 'b2' or 'mylogin_'
// Change this to localize WordPress. A corresponding MO file for the
// chosen language must be installed to wp-includes/languages.
// For example, install de.mo to wp-includes/languages and set WPLANG to 'de'
// to enable German language support.
define ('WPLANG', '');
/* Stop editing */
And also make sure the table prefixes are ok as well. I hope you get this straightened out soon. =)