Hi,
what is your hba1c?
Fasting over 200 is a definitely a concern. How high does your sugar go after meals?
Normal fasting should be < 95 (ideally in the 80s) and you are 2x normal.
Have you had antibody testing, c-peptide and insulin levels testing? This would be interesting to know, as possibly you are type 1 not type 2.
For insulin, bottom line is, you need to normalize blood sugars. When this cannot be done with oral meds and diet (seriously look into strict low carb eating if you are not already) and exercise (exercise decreases insulin resistance), and keeping weight on target, then it is time to add insulin.
I have the same thing due to PCOS which caused Metabolic Syndrome. I tried Metformin but was allergic so now they have me on Glipizide. So far my numbers have been in 100-125 after taking meds. It can drop you down low if you don't eat enough carbs in your meal so you have to be very strict on your routine when taking this med. I eat lean with a healthy balance of lean meats, carbs(fruits and healthy carbs) and tons of veggies. I also do water aerobics and just added strength training. Track with my fitness pal. I would see if your doctor can try a different med. I have lived with PCOS since I was a teenager and diagnosed with high cholesterol in my young 20s, not overweight, and just recently diagnosed with diabetes. Unfortunately, we are cursed with this since it is unavoidable with our disease but can be managed. Good luck to you and take care of yourself!