使用 php 邮件不会插入新行

在下面的代码中，$message在html中显示时有新行（用pre标签包装），但没有在电子邮件中显示它们（我把它发送到我的gmail）：

error_reporting(E_ALL);
ini_set('display_errors', 'on');
include "../code/dbstuff.php";
$to = "me@mail.com";
$from = "";
function processMessage($arr) {
  global $from;
  $message = "Hello from me'n'n'n";
  foreach ($arr as $key => $val) {
    if (isset($_POST[$key])) {
      $message.=$val . ": " . $_POST[$key] . "'n'n";
    } else {
      $message.=$val . ": empty" . "'n'n";
    }
  }
  $message.= "Date: " . date('l F d, Y');
  from = $_POST['contact_email'];
  return $message;
}
$message = processMessage(array(
    "firstname" => "First Name",
    'lastname' => 'Last Name'
));
//save in db
$conn=new db();
$conn->insertMessage($from,$message);
mail( $to,$message,"From: $from" );
header( "Location: thankyou.php" );