Gestational diabetes....

I have gestational diabetes and my blood sugars are not the best but I'm not in the 200s I'm anywhere from 90-171(depending on a few things.). My dr keeps pushing for me to take insulin and I don't want too. I'm on metforman and it seems to be working. I feel super judged and like a shitty person every time they bring up insulin and I say no. My sister has diabetes and was on shots and it made her have seizures she now on the pump and hasn't had a seizure in years. I'm just curious has anyone else had this problem? Has anyone else taken metforman before? I guess I'm just curious about others experience with gestational diabetes?