I think I can feel what you experienced on Sunday @CaspersFriend - frustration. Actually, I know I could be there in your place as I’ve been in that situation so many times over the past 60 years.
Although at this point I have, well have ALMOST stopped letting it bother me and accept that our T1 “treasure” is somewhat beyond what we can control. That said, I do think that with some of the tools now available that we can very well control T1. What do I do in these situations?
If I’m thinking straight when I sense that I’m going low - true, still too often I ignore that “low feeling” telling myself it is my imagination - I take the meter off my hip, check BGL and eat one of the 17 gram carb granola bars I have in my meter holster, if I am below range. I didn’t get to this point on my own, my wife helped - we have been married for only 50 years - by reminding me that I have good management but that out-of-range incidents occur because diabetes has a mind of its own.
My advice, just be wise, do the best that you are able, take a deep breath [and needed carbs] and move ahead.