Fatigue and diziness. Also quite ok.

Sir, I'm senthil.age 40. 2 years before I checked my sugar level and found ,197 at fasting and 350 after post fasting. But I had no Symptoms .After that I do my exercise and diet and now my sugar levels are 148 at fasting and 235 post fasting.and my hbn1 Reading is 8.23% now. Recent times i feel light headness often. And for the past 3 days i feel continuously lightheadness.(so far i never fainted.but feels like that). I consulted a local doctor and checked my blood pressure 120/80 which is normal. He said that  fatigue is the reason and suggest some vitamin tablets.also i have gastro problem in chest. After taking medicines stil i feel lightheadness. Is this problem happened due to diabetics or gastro problem.?? Kindly suggest me further medicines. My cholesterol level also quite ok.