Hi Sir From Last One And A Half Year I

Hi sir from last one and a half year i m facing this problem.i get periods once in 3 months and in that too flow is too low . hardly for 3 days.i want get rid off this problem. Even now 2 months have crossed i didn't get my periods. Please suggest some medicine for getting immediate periods. Because i m having my engagement on 29th of this month. So plz help me.