I've had this fear two times in the past month. I wouldn't wish the fear & anxiety I have gone through on my worst enemy!
Yes, it's very scary to think something like this could happen, but the odds are so very
little that it's silly to even think about.
I too counted down the days and began to have symptoms due to my anxiety tricking me. But hey, I'm still here feeling completely normal!
As hard as it may be, just try to quit worrying and enjoy life. If you can do that, the false 'days of doom' will fly on by!