Hi I Have Diabetes Type 2 I Am Currently Taking

Hi I have diabetes Type 2 I am currently taking Metformin 1000MG twice a day and it seem to be helping until a month are so ago , at which my sugar level has stayed in the two hundreds continuously and I can't get it to go down when but a couple of points . I don't understand what might be happening and I'm very concern !!! Thank You for your Help ~ Marie