Kevin's suggestion to look at the browser console is a good suggestion - you do this by pressing "F12" on your keyboard and selecting the "Console" tab. Also check the "Network" tab for errors (you'll need to reload the page after selecting the tab). Updating the question with info you find there will help people troubleshoot.
Additionally, https://mysite.org/wp-admin/admin.php?page=CiviCRM&q=civicrm/admin will bring you to a page with most of the options on the "Administer" menu, which you'll probably need to fix this. The most common cause of this problem is that your Resource URL is incorrect, or possibly your Directories settings.
This may be a problem caused by your webhost; you may need to check if they created "symlinks" or otherwise moved your file location. If so, you'll need to update the Directories settings to accommodate that (and use the non-symlink version if applicable).