I don’t know how close I was to hypothermia...but...
ONe time I got caught on a motorcycle 20 miles from home in shorts and T shirt when the temp dropped real fast to about 40 degrees F. By the time I got home, I couldn’t feel my arms or legs or my face or my scalp. I was dizzy, had trouble talking(like when your tongue goes numb from licking an icecream cone) and couldn’t walk in a straight line. I almost fell down when I put the bike on it’s kickstand. I could BARELY move my fingers. It took two hands to turn the ignition key off and pull the key out.
I don’t recall any pain. Except a mild headache.
I crawled into a blanket on the floor and laid there for about 4 hours, shivering uncontrollably for the first hour. And I mean shaking like I had epilepsy or something. I was too tired to do anything except lay there. I think all that shaking just completely wore me out from head to toe.
I was very shocked how long it took to warm up.
The shivering actually is warming your body.