stress can indeed raise blood sugar.
The normal hba1c is reassuring. However, what was your actual number.
Many labs give a cut-off of 5.7 for normal hba1c. Howver, 5.7 is equal to an average blood sugar of about 125.
A truly normal hba1c is < 5.0 and average blood sugar < 100.
Now, if your hba1c is < 5.0, I would not be concerned about the spike in fasting glucose that occurred with stress / lack of sleep (though I would want to keep monitoring regularly).
If you hba1c is between 5 and 5.7, then I would take this as a very early warning that I need to be vigilant about managing my blood sugars; exercise, keeping weight normal, eating lower carb diet etc.
Hope this helps.
Dont know the answer to that one sorry.