Hi,
Well done for that 4.5!
Did you experience any wobbliness at having blood glucose lower than usual? Sometimes that can trigger a 'liver dump' of stored glucose, which is when your body triggers the glucose release from the liver to try and bring the blood glucose up to more familiar levels.
It also could have been something else.
Stress, tiredness, pain, worry... Even the heat, or dehydration - they can all affect blood glucose levels.
I wouldn't worry about it unless you see a pattern developing, where the same thing (that food, or that situation) happens repeatedly. Also, sometimes some of us find that certain foods send our blood glucose weirdly high. Gluten containing foods do it for me, and I will let
@Chook tell you about her mushroom situation (hope you don't mind, Chook?)
Hope that helps!