Admin login page does not work

Hello, I’m trying to access the admin page to my wordpress site. Yes, I know that the URL is supposed to be http://www.nameofyoursite.com/wp-admin, but it’s not working for me. When I try to log in to WordPress, it says I do not have an account even though I am positive that I am using the right email account. My Web site looks fine; I just can’t log in to make changes to it anymore. Any ideas? Thanks.