Is It Safe To Take Norethisterone Continuously To Stop Heavy Bleeding?

i starting taking norethisterone for 10 days as i was on my period for 3 weeks and needed to stop my period, after 2 days i started getting really bad pains and heavy bleeding so i went to the doctors and asked for some more norethisterone to stop my periods again and started taking them straight away. is it safe to do this as i have a been showing some side effects.