I've been taking glucophage for almost a year now. The first 8 months aprox it worked great, my A1C went to regular levels and I lost some weight. I stopped taking glucophage for a little over a month because I went on a business trip and simply forgot to get a refill. Ever since I got back I've started taking it again but I've started gaining weight and my A1C is worse. I've been taking it for 4 months now, I'm exercising regularly, my diet is the same as it was during the first 8 months, but I keep gaining weight. Have I developed some sort of resistance to it? Should I do something else?