I know my email, But i lost my username, has as i to recover my account??

contact form or contact a mod via their discord
make sure you know the hashtag of the account in question too, if made before 2018/not name changed it's #0000, if not then it's randomized

Username means "Name #xxxx", So if you lost it you can write your Email instead of the username then write the password and you will see the list of the accounts you have with the same Email !

You can also use the contact form to get in touch with an admin to try and retrieve your account name. Good luck!