Snowchickie, I was on 120+ units of insulin by the end of my pregnancy and the GD went away. You should be able to tell quite quickly after the birth because they will get you to check your BSL's a few times after the birth. Mine were a bit slow to come down, I got around 10 after a meal and my fasting was high but by the second day it was all good. The GD lady in the bed next to me had perfect readings straight away. Try not to worry about it too much, it is unlikely that it will stick around.

Under 4 is considered a hypo. It can happen to anyone but it is more likely when you are on insulin. I fell asleep once and missed morning tea and when I woke I was sweaty and it was the biggest effort to get to the kitchen for food. My reading was 2.2. It happened a few times, if I did more exercise or missed a snack (walking around Ikea always gave me a hypo lol)