My New Site admin approval
When you installed Drupal you should have had to setup a main account: 



That is the login you should be using, if you don't know that password go to /user and click Forgot Password and you can retrieve your login if you remember username or email you used. Since you got (Pending Admin Approval) it should be that email that is registered as main account. 

(Pending Admin Approval) emails are sent when someone else tries to register an account on your site.