just include:
if(empty($_SESSION['user_id']) && $_GET['page'] !== 'login'){ header("location: index.php?page=login"); die(); }at the pages where you need to be logged in.
if(empty($_SESSION['user_id']) && $_GET['page'] !== 'login'){ header("location: index.php?page=login"); die(); }at the pages where you need to be logged in.