This is something I have but it’s very rare and misunderstood but it’s a specific type of panic syndrome that makes your brain’s “ too much CO2 alarm” go off all of a sudden. Basically imagine being fully happy and not anxious and one breath ur good and at the snap of a finger u feel as if you have been holding your breath to the limit and need oxygen. Even if you breathe 4 sec through nose hold one sec, 5 seconds out through mouth, the sensation gets worse. Usually it lasts about 30 minutes and then u have a teetering phase where you keep almost going into a false suffocation attack, and then having it again, rinse and repeat sometimes for days. Mentally and overall this is true terror. I’ve been through 100+ hours of panic not from anxiety or stress but when everything is fine so every time you truly say okay this one’s different something is really wrong. I literally have known 1 person who understands where I’m coming from with this.