I had a sister who was diagnosed with Diabetes I in her youth so our family is predisposed to diabetes. I had a scare when my blood sugars were skyrocketing overnight. Early in teh morning, the readings were through teh roof, but, by evening, it was down to normal. As it turned out, I had an infection somewhere that was boosing teh blood sugars at certain times of the day. Once I was on antibiotics, the blood sugars fell back to normal.

Not ignoring the other factors, like medications and diet, also consider possible infection. That will boost your blood sugar levels also.