Hi. Diabetes can be a progressive condition, so it may worsen over time, even with your best efforts.
Another thing that may affect BG levels is illness / infection - even mild ones. For example an oral infection, fighting off the flu.
You can try increasing physical activity / reducing carbs, which may help. If levels still remain elevated, you may wish to discuss treatment options with your Dr.
Stress pain illness can all raise BG some people get BG rise before they know they are sick.