Discouraged and new

I have been checking my blood sugar since I was pregnant and had gestational diabetes. Everyone seemed surprised with the diagnosis, I'm not overweight and a pretty healthy eater. My numbers were really easy to control. Post prandials and fasting always in range. Baby boy is born, everyone expects diabetes to go away, I pass my oral glucose tolerance test at 6 weeks post partum. It has been an uphill climb since then. Literally -- My A1c creeping up slowly until I hit 6.2, without changes in my diet, my morning fasting glucose slowly going from the 70's to the 120's. I was put on 1000mg of metformin, with no changes in my glucose numbers. I have always been an avid exerciser (I live in a bike and pedestrian friendly city; cycling, running and mountain climbing are part of my routine) and always conscious about carbs: Can't remember the last time I ate a banana, or bread, yet all I hear is eat healthier and exercise more. Finally I'm 5'3, 120lbs, everyone raises an eyebrow when I tell them about my blood sugar struggles, but my doctor seems to think this is because of my really strong family history. Is that all there is? Should I just settle in and never eat above 15g of carbs per meal, because otherwise my sugar goes up into the 170's? I'm bummed. Still new at this, and running out of ideas.