What's interesting about those numbers is that none of them are lethal. Although 60ish is uncomfortable, at least for now, the body is somewhat maintaining it to survivable levels. The reason you feel so bad is likely because of the quick drop, not the actual Sugar level. I'll bet this is my problem too.
I wonder if this is due to low cortisol, high insulin or both?
Since the lower numbers are just before you eat my guess is low cortisol, but that's just a guess.
A friend of mine who is type 1 had a reading of TWELVE!!! He went unconscious and his veins collapsed. The EMS guys barely got the glucogon in his blood. Scary.
Thankfully for us, this is highly unlikely. Lethal hypoglycemia is typically caused by insulin mis-dosage.