contact form, message is not recived

Question

I need to make a contact form and I did, but when Im sending test message Im not reciving that message, I have check my email addres and test message never get there i also looked into spam folder but still no luck how to fix this? here is my code

<?php

$formMessage = "";
$senderName = "";
$senderEmail = "";
$senderMessage = "";

if ($_POST['username']) { // If the form is trying to post value of username field

// Gather the posted form variables into local PHP variables
$senderName = $_POST['username'];
$senderEmail = $_POST['email'];
$senderMessage = $_POST['msg'];
// Make sure certain vars are present or else we do not send email yet
if (!$senderName || !$senderEmail || !$senderMessage) {

     $formMessage = "The form is incomplete, please fill in all fields.";

} else { // Here is the section in which the email actually gets sent

    // Run any filtering here
    $senderName = strip_tags($senderName);
    $senderName = stripslashes($senderName);
    $senderEmail = strip_tags($senderEmail);
    $senderEmail = stripslashes($senderEmail);
    $senderMessage = strip_tags($senderMessage);
    $senderMessage = stripslashes($senderMessage);

and here is part which im not sure about

// End Filtering
    $to = "test@gmail.com";         
    $from = "contact@your_website_here.com";
    $subject = "You have a message from your website";
    // Begin Email Message Body
    $message = "
    $senderMessage

    $senderName
    $senderEmail
    ";
    // Set headers configurations
    $headers  = 'MIME-Version: 1.0' . "rn";
    $headers .= "Content-type: textrn";

    // Mail it now using PHP's mail function
    mail($to, $subject, $message, $headers);
    $formMessage = "Thanks, your message has been sent.";
    $senderName = "";
    $senderEmail = "";
    $senderMessage = "";
    } // close the else condition

   } // close if (POST condition
   ?>

here is html form

<form id="form1" name="form1" method="post" action="contact.php">
<?php echo $formMessage; ?>
<br />
<br />
Your Name:<br />
<input name="username" type="text" id="username" size="36" maxlength="32" value="<?php          echo $senderName; ?>" />
 <br />
 <br />
 Your Email:
 <br />
 <input name="email" type="text" id="email" size="36" maxlength="32" value="<?php echo      $senderEmail; ?>" />
    <br />
    <br />
     Your Message:
    <br />
    <textarea name="msg" id="msg" cols="45" rows="5"><?php echo $senderMessage; ?>   </textarea>
    <br />
    <br />
     <br />
     <input type="submit" name="button" id="button" value="Send Now" />
      </form>