I think how you feel at hypo also depends on what bg you've dropped from and the context ie if you are moving about, sitting down etc.
Eg just after diagnosis I would feel hypo coming down to 8, most likely due to running higher for weeks prior to diagnosis. However, the other day I was in low 3's but didnt realise, I think because I had been sitting still watching TV and only felt something when I got up to go take bg pre dinner. Sometimes I get vague feelings which I didnt always test (because on lots of occasions, same feelings have yielded ok or higher bg) but now I just test the minute I feel something funny.
When in was in hospital the weekend of dx I was on actrapid drip and with hourly bg being taken. On one occasion nurse came to take it, I sat up to offer my hand and felt very strange. Nurse thought I had just sat up too quickly but then ran out the ward lke the proverbial bat out of hell and returned with hypostop and then put a glucose drip in.On checking chart the next day my bg had been 0.5. I dread to think what would have happened if it hadnt been the 'on the hour' time to test. Explain that to my family if something had gone wrong.
As I was so shocked re dx, exhausted etc etc, I didnt feel any different until I sat up and given it was the early hours of the morning, if i had become unconscious it would have just looked like I was sleeping.
Doesnt bear thinking about.