I have been taking Metformin on and off since 2008/2009. I first started taking 1,000 mg twice a day, I also test twice a day. I then noticed that my blood sugar was staying a little below or right at the required level so I stopped taking Metformin. then my current doctor said my A1C was 6.9 and she wants me to start taking 500 mg a day. I do get some stomach pain, headaches, and lightheadedness, but have not been diagnosed with anything for it. what should I do?