HI, I understand your query. Postinor 2 is a high hormone containing drug use for emergency contraception. It tends to cause disturbance in normal cycle by at least a weeks delay in period. You had taken it for 3-4 times in a month.. it was too much for body to bear, as it had caused lot of hormonal changes over one months period.. causing lot of congestion in the pelvic area. This has resulted in pain inback as well as lower abdomen & also irregular brown discharge. I would suggest now, to wait & watch for withdrawal bleeding in next 15 days. If it does not occur, consult a gynecologist. - Be careful to maintain good genital hygiene, - Never ever use Postinor as a regular means for contraception. It s better to go for an oral contraceptive monthly for a continuous contraceptive protection. Thanks.