表格不会发送邮件

I made a from in php and it seems to work. When i hit the submit button it goes to the next page and show the message has been send, except i don't receive anything in my mailbox. Probably easy to fix but I'm pretty new at this all and tried all afternoon yesterday and running out of ideas.

<form class="well" method="post" action="form.php">  
<label><b>Klantgegevens</b></label>  <br>
<span class="inline span2">Winkelnaam</span><input type="text" name="winkelnaam" class="span10">  
<span class="inline span2">Straat</span><input type="text" name="straat" class="span10">  
<span class="inline span2">Huisnummer</span><input type="text" name="huisnummer" class="span10">
<button type="submit" class="btn btn-info">Verstuur</button>
</form> 

This is the form.php

<?php 
$winkelnaam = $_POST["winkelnaam"];
$straat = $_POST["straat"];
$huisnummer = $_POST["huisnummer"];
mail('xxxx@xxxx.nl');  
echo 'Uw bericht is verzonden.';
?>

You did not provide a mail subject and mail message. See PHP mail() documentation for more info.

mail('xxxx@xxxx.nl', 'My subject', 'Mail message text here');

mail('email@address', 'Subject', 'Plain text message', $optional_headers);

But I recommend using a framework to send email instead of the mail() function. Take a look at http://swiftmailer.org/