It's one of my anxiety's meanest tricks, apart from fucking with my vision/hearing. It especially likes to show up during situations where I'm actually feeling relaxed. Just chilling on the couch and then my body's like "uh oh, oxygen's wonky, uh oh". It's often accompanied with a sudden cold wash. Logically I know I'm fine (probably lol) and I ride it out, but it's just frustrating, especially when I try to take a slower, deeper breath and feel zero improvement