I have long covid and during the initial stages I had some really bad tachycardia (unknown to me yet) that caused breathing issues. It hadn't been too bad until one day I was lying in bed unable to sleep, and suddenly I feel like every breath is getting me less and less air, even though I'm breathing normally.

I woke up my mom at ~4:30 AM (home because of long covid) and said I feel like I can't breathe. She asks if it's bad enough to go to the ER, and I say it might be. I decided to wait 15 minutes, my heartrate was going crazy and I must just be panicked, and that's why my heart rate is high and why it's hard to breathe.

Over those 15 minutes my heart rate climbs higher and I'm getting dizzy and hyperventilating and still breathless, and say I need to go now, I think I'm at the edge of where I could actually die.

We drive to a hospital and my heart rate slows down a little bit, and I figure I'm not gonna die in the next hour so I end up waiting, struggling to breathe, until 6AM when my primary care opens his office. They do some tests and say everything looks normal, but later a heart monitor would show my heartrate sometimes get to ~120, even while I'm lying in bed trying to sleep. I eventually learned that is what causes the breathlessness.

I've had that happen a couple times since, less frequently it seems, but when it does happen I'm always afraid that this is the time my heart finally gives out. Fortunately it's very rare and I've been able to do some cardio to hopefully help it be even more rare.