Have been diagnosed with GD since about 8 weeks

Katelyn
I have been diagnosed with gestational diabetes since I was 8 weeks. I am now going on 14 weeks. 
My daughter who was born in 2013 was 9.2. When I was born I was 8.8 and my husband was 9.2 as well. The main concern for my doctor is the sizing of our babies in the family along with the GD which could make the baby even larger this time around.
My fasting blood sugars are slowly starting to rise(the only sugars that are above normal). Once they get to 95 and above, my endocrinologist said she would be putting me on insulin. Why do I see others getting put on medication such as metformin or glyburide instead of insulin. It will seriously suck to be put on insulin for 26 weeks. I am sure I will see her again before my next appointment if my sugars are above normal. Just looking for input, thanks!