Why php text appear if i dont even write anything?

Question

look im making a login and im trying to display on screen after the cliking the login your textbutton "This email does not exist" but its showing without typing . I just want the text "This email does not exist" to appear after I write the email itself in the text box and search the database.The text in the middle between the login text and login box. Login

$sql = "SELECT  `email` FROM `utilizadores` WHERE `email`='$emaillogin' ";

$result = $conn->query($sql);

if($result->num_rows == 0) {
   echo '<p>Email não existe na base de dados</p>';
}

I tried everything but its still showing