I know the feeling, having had that same experience of missing out on shows due to illness, and it really sucks that you had tickets to this show you couldn't use! It brings back a not-so-good memory of the time back in 1983 (same year as the show DSO decided to recreate here) when I had two tickets to see Elton John at Merriweather Post, and my friend who had a car got sick and let me know the morning of the show that he wasn't gonna make it. Much as I tried, I could not find another ride, and of course there was no such thing as Uber, and I wasn't willing to hitchhike from DC to Columbia, MD, so I stayed home. I still have those two intact tickets!
By the way, welcome to the boards, and may you be feeling good and healthy for your first DSO show in the not so distant future!