Cannot access my site

After I log into my site administration, and I’m on the site’s homepage, I cannot access any of the WordPress administrative pages. Every time I click on a link to the Posts page or Plugins page or another page, I’m redirected to a page that displays the WordPress logo and a message that says, “No Update Required Your WordPress database is already up-to-date!” When I click on the “Continue” button, nothing happens. No matter what I click on my site, I cannot escape this page. Any help?