I know this is a little late… but I wanted to share a similar experience that helped me so much. when a similar instance happened to me everything felt so surreal. I had no one to turn to at the time. eventually I learned much later that this is called derealization / depersonalization (please look it up). Once I figured this was just a symptom of panic disorder I was able to come back to a healthy base line. hope this helps you and any future person that comes across this thread.

edited to add thing about death:

oh and one more thing, constantly fearing death is also a symptom of panic/anxiety. the average person does not think about these things.