I was wrong about the reason.
I woke up today feeling really sick. I ignored it, because I always feel a little bit sick in the morning, so what's a little more sickness than I usually feel? It usually goes away anyway, and even though this sickness persisted, I thought it would just go away once I hit an hour I normally wake at.
I went to the Y for my tae kwon do workout, and the sickness briefly felt gone...but then it got worse. Much, much worse.
Only once, but that's because there was nothing else for me to vomit up.
I have had brief periods where I thought it was just a momentary sickness. That I was making it up, that it was not as bad as I thought, that I was just having bouts of sickness and was actually just fine. Periods where in that bout I thought that I would be fine, I would recover, I was actually well, and I could go on with my day.
...And then the waves of sickness hit me strongly as a reminder that no. I am not imagining it. I am not exaggerating it. I am not making it up. I am not temporarily sick. I am just flat-out outright sick. Sick to the point where I can't even drink water without the risk of vomiting. No joke, I put a single mouthful of water into my mouth...and then immediately spit it out when my body warned me that if I swallowed it wouldn't stay down.
Reflexively I just knew.
Just...ugh, I'd have preferred the suckiness of working to the suckiness of vomiting-sickness.