You're a Diabetic and you self adjusted the dose of your OHA's based on the glucometer test result.
This is a very bad practice. You should not self adjust the dose by your own without the advice of your doctor.
If the glucometer readings are wrong you may land in severe persistent hypoglycemia
which is life threatening.
The glucometer reading are not accurate and reliable always for many reasons.
It is more sensitive to hypoglycemia than hyperglycemia