Many people find their fasting morning reading is higher than expected. A frequent cause is the dawn phenomenon, where hormones released in the early hours signal the liver to release glucose to prepare you for waking, naturally raising blood sugar.
Other contributors include eating a large or late-night meal, the timing or dose of evening medication, and occasionally a rebound after an overnight low. Because these have different solutions, the cause matters.
To understand your pattern, your care team may suggest checking levels overnight or wearing a continuous glucose monitor for a period. Resist the urge to adjust insulin or tablets yourself, since the wrong change could cause lows. Bring your readings to your clinician so any medication timing or dosing decisions are made safely.