Ketone and glucose readings help please

Hello everyone, I’m one week into my 3rd month on keto and have been eating under 19 carbs per day consistently. My blood ketone levels have been between 3-5. My glucose has been between 78-90. However, beginning this week, my ketone level has stayed between 1.6-2. And my glucose has been between 105-115. I’ve changed nothing since day one. I take both readings the same time of day, after coffee, before breakfast. I’m at a loss to understand why the drop in ketone levels with a rise in glucose. Can anyone help me understand what’s going on? Thank you all for reading this and I appreciate any and all help with my situation. Thanks