fetchmail forwarding to gmail via procmail - what is happening?

Question

I've set up fetchmail with the following configuration

poll my.exchange.server protocol IMAP
   user "my_name"
   password "my_pass"
   smtpname "my_gmail_account@gmail.com"
   ssl
   keep
   no rewrite
   mda "/usr/bin/procmail -f %F -d %T"'

Everything seems to be working fine. No errors from fetchmail, and the procmail log contains the e-mails that I want to be forwarded to GMail (an example is pasted below). However, none of the mail ever shows up in my GMail inbox. I've checked the 'All Mail' section to ensure it wasn't being treated as spam. Any ideas what could be going wrong? I'm doing all this on OS X version 10.8.5

Example procmail log for an e-mail that I want to show up in my gmail inbox

From my_exchange_email@my.exchange.server  Mon Sep 30 11:03:55 2013
MIME-Version: 1.0
Received: from my.exchange.server [123.45.678.910]
   by my_host_name with IMAP (fetchmail-6.3.26)
   for <my_gmail_account@gmail.com> (single-drop); Mon, 30 Sep 2013 11:03:55 -0400 (EDT)

Answer 1

I figured out what I was missing. My procmail was configured incorrectly for forwarding. I fixed this by making the following procmailrc file

:0:
! my_gmail_account@gmail.com

That was it!