Next steps?

I’m 15 weeks, 2nd pregnancy, and was on 1000 mg metformin for insulin resistance before I got pregnant. I had GD last pregnancy that was well controlled with 1000 mg metformin- my fasting numbers were high before this.

Waiting to see MFM and since my fasting numbers are high again, my OB suggested 1500 mg of metformin at night. No matter what snack I have (cheese stick, some popcorn and a protein shake and cheese stick, no snack) at night, it’s still high in the morning.

I think I’m on the road to insulin, any other suggestions? And also how does insulin work for fasting numbers?