Why Have I Not Conceived Yet Despite Being On Susten VT, Folic Acid, And Metformin For Irregular Periods?

Hi ... I been married for 2 years and I had irregular periods for 2mnths in the month of sept and then my doc prescribed me oval L and metformin tab ... In March she put me on Susten VT and folic acid tablet along with metformin... But now I got periods on time without stopping susten VT .. I m overweight for my age my reports all are normal .. including the ovary size ... Not sure why I didn t get pregnant