Obgyn diagnosed me gestational diabetic

I'm 15 weeks and my obgyn asked me to do a early sugar test due to my age of 35. I did and I failed the one hour with a 160. She done a A1C test and it showed my level is 5.7 and average blood sugar was 117 over the 3 months. I've been checking my sugars and eating 180 carbs/2000 calories per the nutritionist. However, my average fasting number is 88 and 1 hour after meals is 102-107. My doctor said I may need medicine due to high sugar numbers at 1 hour? The nutritionist said my sugars are great. Anyone ever deal with this?