Why Haven’t I Gotten My Period After Taking Cycloreg For 3 Days, Following Missed Periods Since Blood Donation?

Hii .... I had donated my blood On. October 2 nd nd I got my periods on 15 th nd the ntx month September I dint get my periods nd November also I don t get ..... So my frd suggested me to take cycloreg tablet for 3 days ... I took it thn too I dint get my periods wat will be the problem??