Check your meter. It could be that if you dropped it or left it in a hot car, it is now defective. They usually are only good for 2-3 years, too. Run a test on the meter with the sugar glucose fluid you have and a fresh test strip. If it is out of range, it could be the meter. Ask your doctor for a new one.
Illness can raise BG so can infections
What do YOU call a propper diet?
carbohydrates raise BG, whole wheat, brown rice, potatoes all raise BG
Diabetes is a progressive disease. I would suggest you consult with the physician or RN managing your care and discuss adjustments to your insulin.