One of the experiences I’ll never forget was a moment when I was maybe 13 or 14 years old. We had a big winter snowstorm and I was the one outside shoveling. The snowblower worked well until I started doing my neighbor’s driveway. It conked out on me only a few feet in (and it was a LOOOONG driveway). So I started doing the rest by hand.
Despite my youth, I was very quickly depleted of energy. The snow was heavy, no one was helping, and I got so weak to the point I just collapsed on the snow (not fainted; just laid down for a few seconds). My brother was laughing and finally came out to help finish the job.
I went back inside and felt so weak that my mom recommended I take a bath. While sitting in the water, I noticed a bunch of red dots all over my body. It wasn’t chicken pox. It was like clusters of red dots that formed a rash or something. I didn’t know what it was, and neither did mom. So she recommended a trip to the hospital. And it was a good thing I went when I did.
After some bloodwork, it turns out that I had that I had low red blood cells. Like dangerously low. So I had to stay in the cancer ward for three days (apparently that is where the equipment was that I needed). They kept me hooked up to an IV and I was limited to the bed that entire time.
Eventually I got better and went home. Never again did the symptoms reappear. There was no specific cause other than a possible virus (like a cold) that stayed inside me even though the physical symptoms went away.