You do not want to mess around with blood sugars during pregnancies.
I spent 8 years in the world of diabetes selling insulin and other hormone-based injectible medications.
Rule of thumb: being diabetic is just like being pregnant. You either are or you are not. There is no borderline. If they told you your test came back positive, you are, and you need to be referred to an Endocrinologist, a Certified Diabetes Educator and a Dietician (who may also be your CDE).
When I started in Diabetes in 2001, there were an estimated 17million people in the US with Diabetes. Today, there are almost 25 million. 1/3 of the people who have diabetes don't know it because doctors aren't doing a good job of following American Diabetes Association guidelines for diagnosis.
In general, if your Fasting Blood Sugar (before you've eaten) is over 126, you have diabetes. If it's over 180 after a 2 hour glucose tolerance test, you have Diabetes. Plain and simple.
Your target ranges should be below 126 mg/dL for FPG (fasting plasma glucose) and under 140 mg/dL for PPG (post prandial glucose - 2 hours after meals).
Good luck - please see a Certified Diabetes Educator. Insurance will cover the costs, and they know Gestational Diabetes much better than your OB.