If 148 is the average reading for your fasting blood sugar, than that is diabetic level. Fasting
blood sugar readings should be less than 100 and ideally 80-90. Unless you know what your
blood sugar readings have been with and without food, you can assume from your reading of 148 IF it's fasting, that you have had diabtes all these years. I am surprised that your family doctor did not keep on top of this.
I am a former diabetic that was insulin and pill dependent.