I am trying to get the username of my users to echo out but only seeing the userID or if I try to echo the username it gives me the string length rather than the actual name.
the reason you do not see the user name in:
$_SESSION['username']
is because you never put it there.
you need to assign the user name to the session like so:
$_SESSION['username']=$email;
you can then echo $_SESSION['username'];
where ever you want the username displayed.
make sure on any page you use sessions you have session_start();
before any output.