your irregular periods
might be because of Poly cystic ovarian disease
because of that your doctor might have prescribed BIGOMET(metformin) to you,
as insulin resistance
is a feature of PCOD, this drug help as insulin sensitizer,
along with this better to take ovulation induction
drugs which will increase the chances of fertility,
so you better consult your doctor once undergo ultrasound to find out present stage of PCOD then take treatment accordingly.