Near Death Experiences

I sort of classify what happened to me as a near-death experience. 

For backstory: I was in either fourth or fifth grade at the time and I had stayed home because I had a growing, sitting, type of pain in my chest from when I had woken up for school. And progressively throughout the day it had gotten more, and more weighed down until we eventually had to drive to the hospital, and go to the emergency room. (We later learned that I had a severe asthma attack, and if I had been any later I more than likely would have died.)

I haven't told anyone else, not even my family what I had seen for fear that they might think I'm crazy. But I swear that when they were trying to regulate my breathing, getting needles for fluids into my arms, and switching me from the emergency bed to a medical bed. That during all of that when I, think it's called "tunnel vision"(?) because I was near passing out, but I was looking out into the hall and when I looked towards the corner that was before my "room" (one of those fast emergency rooms), I SWEAR I saw a tall black fog make its way around the corner and look towards me. But right at that time was when I had either a doctor, or one of my parents start to try and keep me awake, and that's when the black fog went somewhere down the hallway. And after that, I haven't seen it since. 

But I still find it weird, because I still remember every feeling from that memory like it was in the third person perspective. And it's weird too because I remember looking at the black fog and just feeling a really calm, and serene feeling, like no fear or anything. I almost feel like it was the Grim Reaper waiting, and then seeing that I was gonna make it, and decided to just leave me be and go to someone else.