PHP form - stött på ett litet problem

if($_post['submit']) {

	<?php } if($sent == true) { ?>

	<p class="sent">thank you, your email has been sent successfully. we will be in contact with you shortly!</p>

<!-- form start -->
<?php
if($_post['submit']) {
	if(empty($_POST['name']) || empty($_post['email']) || empty($_post['message'])) {
		$error = true;
	} else {
	
		$to = "alexandersjoberg89@gmail.com";
		
		$name = trim($_post['name']);
		$email = trim($_post['email']);
		$message = trim($_post['message']);
		
		$subject = "contact form";
		
		$messages = "name: $name \r\n email: $email \r\n message: $message";
		$headers = "from:" . $name;
		$mailsent = mail($to, $subject, $messages, $headers);
		
		if($mailsent) {
			$sent = true;
		}
	}
}
?>
	<?php if($error == true) { ?>
	<p class="error">there was a missing field on the form. please make sure you enter your details and message in all the boxes provided.</p>
	<?php } if($sent == true) { ?>
	<p class="sent">thank you, your email has been sent successfully. we will be in contact with you shortly!</p>
	<?php } ?>
	
	<div id="contactform">
	
		<form name="contact" action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post">
			<label for="name">name:<br></label>
			<input type="text" name="name" />
			<br><label for="email">email:<br></label>
			<input type="email" name="email" /><br><br>
			<label for ="message">message:</label><br>
			<textarea name="message" cols="25" rows="6"></textarea><br><br>
			<input type="submit" name="submit" class="submit" value="send" />
		</form>
		
		<div style="clear:both;"></div>
	</div>
<!-- form end -->