Despite the fact that I did not receive any sort of apology or acknowledgement of my response to the parent e-mail I got yesterday, I'm feeling a bit better.
Tonight, my own son had a school concert. He plays trumpet in band, plays chimes and sings in the chorus. It was nice to relax and watch his hard work come to fruition. (It was not nice that we were surrounded by people who chatted through the whole concert.) I'm very proud of him.