Well assuming that its not just a meter malfunction its possible you had a reactive hypo. This happens when someone still has pancreatic function and is on the road to diabetes. Basically what happens is because your bodies primary insulin response isnt working as well as it should your blood sugar rises quite high but then your secondary insulin response will kick in but will actually produce too much insulin and make you hypo. Its fairly common thing that most people with type 2 will have experienced over the years before becoming full on type 2.