My latest fasting blood test showed an a1c of 5.9 and blood glucose level of 87. I am at a healthy weight & scared of diabetes. How bad is it?

At Risk. So the fasting glucose of 87 is great. Your HBa1c puts you in the risk/ impaired range. I hope your BMI is in the 25 range. Patients of mine who cannot lower their HBa1c below 5.7% are considered for metformin or other oral therapy. Glucose testing may be needed. You most likely have issues with post glucose spikes. Would recommend you speak with your provider about family hx. .