remove this code:
echo "we are here"'
the exit line will stop the script from processing
make sure there is no redirect to another page, and add the following code at the bottom:
<?php var_dump($_SESSION); ?>
this will write the session contents the screen, the session will contain a status of the email to let you know if it was sent to the SMTP server successfully or not, if the status is successful, then you'll need to lock at the SMTP Server settings you are using, if it is not successful, then look at the from and to email address settings.