In your database, under nuke_authors
See if your admin user name is there. It should be.

The 'aid' field will be your admin name and the 'name' field should be 'God'

If it is not, then you can run this query to insert the God account back into the nuke_authors table

Code:

INSERT INTO `nuke_authors` VALUES ('admin', 'God', '', 'youremail@yoursite.com', '5f4dcc3b5aa765d61d8327deb882cf99', 0, 1, '');

The login would be username:admin and password would be 'password', without the hyphens. Then you can login and change your password once you are in.