Sounds so much like what's happening to me here, yet how to distinguish between the "real thing" and confirmation bias?
One day, I was at my desk, speaking on the phone with a work colleague. On my side, there was another colleague also speaking to me. I started to see everything blur. I tried to speak but I couldn't. Started to feel a huge pain in the chest. I remember putting my hand against my heart and then passed out. - When I recovered my senses (a couple of seconds later), I couldn't feel my legs, I was shaking, and couldn't speak. It was terrifying. I really though I was having some sort of heart attack. In the end, was a really bad burnout, stress, altogether. I'm still doing my job (sysadmin), but I don't know how long will I be able to stand this.
So, take care!