Yesterday I was short on sleep, and I never quite recognized it fully but I was also fighting with low-to-medium levels of anxiety all day. Anxiety is partly caused by tiredness and then it eggs on the tiredness; it contributes to physical symptoms like muscular tension and a squidgy stomach, and then it points to those things and suggests to me that they are a sign my body is about to catastrophically fall apart.
Darn sneaking stuff, anxiety. Everything it does is designed to feed itself and make it worse. But it never comes out and says "ha, Crispy, you're fighting with your old nemesis anxiety today. I'm going to make you feel crappy and there's nothing you can do about it. Thppppt." It doesn't show its face openly, and it pretends that it's not really as big a deal as it is. It suggests that maybe it is making everything else a little bit worse, not that it is the main thing which makes everything feel off.
I'm on to its tricks today. I'm using every tool I have to knock it down and cut it to pieces. This is the benefit of experience; I've been here before with anxiety nonsense, and I know how to fight it. If I can just learn to recognize it earlier and cut it down before it starts growing, I'll be on to something.