PHP script doesn't send email only downloads php file - php

Question

Hi Im trying to get a contact us page to get a email address and send it to an email. Everytime I click submit the php file just downloads. I have loaded php version file on the web server and its running php version 5.3.27 code below:
<?php
if(isset($_POST['email'])) {
// EDIT THE 2 LINES BELOW AS REQUIRED
$email_to = "nishantrama#gmail.com";
$email_subject = "Sva Sva Spa Salon Coming Soon Notify Email";
function died($error) {
// your error code can go here
echo "We are very sorry, but there were error(s) found with the form you submitted. ";
echo "These errors appear below.<br /><br />";
echo $error."<br /><br />";
echo "Please go back and fix these errors.<br /><br />";
die();
}
// validation expected data exists
if !isset($_POST['email']) ||
died('We are sorry, but there appears to be a problem with the form you submitted.');
}
$email_from = $_POST['email']; // required
$error_message = "";
$email_exp = '/^[A-Za-z0-9._%-]+#[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$/';
if(!preg_match($email_exp,$email_from)) {
$error_message .= 'The Email Address you entered does not appear to be valid.<br />';
}
$email_message = "Form details below.\n\n";
function clean_string($string) {
$bad = array("content-type","bcc:","to:","cc:","href");
return str_replace($bad,"",$string);
}
$email_message .= "Email: ".clean_string($email_from)."\n";
// create email headers
$headers = 'From: '.$email_from."\r\n".
'Reply-To: '.$email_from."\r\n" .
'X-Mailer: PHP/' . phpversion();
#mail($email_to, $email_subject, $email_message, $headers);
?>
Any everytime I click submit on my webpage it just downloads the file.