Gestational diabetes oddities

I was diagnosed with gestational diabetes. I failed the initial glucose test and the second 3 hour test. I had low blood sugar prior to being pregnant. The Dr's have me charting everything I eat as well as sugar counts 4-6x a day. Recently I encountered low blood sugar as well as high regardless of what I eat. E.i. I had high sugar with a homemade salad but very low sugar with a sausage muffin. Has anyone experienced this type of "gestational diabetes"? What causes both low and high? What was the end result?