Hmmm... it happens from time to time (and August is always bad for this kind of thing - holidays!), but they really should have told you know if there was going to be a delay. Give 'em a call, and ask when you should expect to hear. Regardless of what the answer is, you'll be able to stop fretting, and if the news isn't good, you can get some feedback that should help you next time. You have nothing to lose by reminding them that you are still waiting. Good luck!