Talk to Gynecologist on Missing /no Periods, Hairfall Issue,black Stool/feces

Post anonymous.My sister(unmarried,21)complained about missed periods for more than 5 months.Before 5 months:doct prescribed diane35 had it for12 days then periods came. Nxt mnth periods did not come on thatday Then she took diane 35 again for about9 days then the periods came but it lasted for only 3 days. Then again next month she had no periods then there was gap of 5 mnth with no periods.A month back hakeem suggested "karshi khatooni syrup".She had 3 of those still didnt get periods.In 2020 the periods were only3/4 times in whole year. Back in 2015 she went for hajj and took tablet for delaying periods.Also, hairfall led to patches with no hair nd thick hair on private areas.She has observed that lately she is getting black feces/stool with white speck or worm like, cant figure out that.What tests should we go for?What underlying problem is this pointing towards that she is having no periods for a long time? What is the cause of black feces/stool?Plz give leads for experi