Hi, in my experience it v is nut just carbs but also total calories, and physical activity that affect your blood sugar. You need to look at pattern over time rather than just 1 or 2 days, results. Stick with low carb, exercise, and keep monitoring.
Lots of things effect BG
For one thing your meter has a 20% error in it so your BG 92 and 108 could be the same
92 X 20% = 18.4 added to 92 meant your actual BG could have been 110.4
And BG always changes, so you will unlikely get the exact same reading every morning.
You dont say if you have been DX as prediabetic or not but diabetes IS the body's in ability to properly regulate BG, so one would expect changes in BG
Infection or illness can raise BG even before you know you are sick.