That's fasting, right? Lots of things can affect the fasting blood sugar. If you did any exercise in the morning before your blood test, if you had a big meal the night before with more carbs than usual, dawn phenomenon, stress (in general and specifically in the doctor's office), sickness (that is, your body is trying to fight off sickness but you're not sick
yet) - all this.
You get a lot of exercise! It would be interesting to see if there's a difference in fasting if you don't do any exercise at all the whole day before and the morning of the test.