I Had Only 10 Days Gap Between My Period Cycle

i had only 10 days gap between my period cycle from six months back. The gynaec prescribed deviry 10 mg to be taken from 11th day of my period for 15 days for three months to regularise my period. Last month after stopping the tablet i got my periods after 3 days. However this month, its been 12 days now since i stopped deviry tablet, yet i have not got proper periods. there is dark blood color discharge however for 10 days now and lot of discomfort and uneasiness in the abdomen. please guide.