Norethisterone and the return of normal periods

[QuizTeamAguilera]

I took Norethisterone to delay my period in November. I took it for 4 days and had a normal period that began four days after I finished taking them. That was on 18 November and I haven't had a period since.

I am 51 with no signs of menopause, definitely am not pregnant (have been sterilised) so was wondering whether this is sometimes what happens with this drug? Otherwise very puzzled.