I have lost my website!

back to FTP and upload your theme again?

your data isn’t gone, it’s in your SQL database. As macbrink wrote, reload the theme.

yup, don’t panic… All is not lost! You should still be able to login using https://www.mydomain.com/wp-login.php as the login page doesn’t rely on your theme. Once in you should activate the default theme, if this works when you view the site you only need to upload your old theme again, activate and your back in business!!