Your irregular periods
are due to polycystic ovaries
. The medicine given to you will regularize the period only for the period during which you are taking medicines or for 1-2 extra months beyond that. If you don't want to conceive you can take the medicine as long as you wish. If you want pregnancy
is better to go for some form of ovulation induction
with tablets. For long term management you need to modify lifestyle with healthy diet & daily regular exercise for at least 30min.
(As I was not knowing whether you are married & trying for pregnancy I have advised comprensive management. Take whichever is applicable to you).
Wish you good health.