Metformin!?

Had D&c in may 2015! Went back to doc November 4 to start trying again, she prescribed metformin! 500mg 1a day for two to three weeks then up it to 2 a day! Took it for two months, cycles were 36 days! Went back January 18 she upd dosage to 3 a day and tomarr is CD36! I feel it's messing periods up even more! Anybody have any good or bad ttc stories with metformin?