Cant access wp-admin

One thing you can try is to disable your plugins

http://www.wpbeginner.com/plugins/how-to-deactivate-all-plugins-when-not-able-to-access-wp-admin/

if that does not work, you can disable your current theme by renaming it, the folder is ‘wp-content/themes’ you open it with ftp and rename your current theme.Make sure you have another so WordPress can switch to that.

also before making any change you can take a full backup just in case : )