What Causes Irregular Periods Despite Taking Progesterone And Norethisterone?

Hi doctor....i normally will not have my period on my actually date...it will skip 1 or 2 weeks from my actual date every month...some month it will come on the actual date..but now, my period start 28/2/17 and ends on 6/3/17. And it start back on 15/3/17 but very light bleeding. Then i went to see doctor....the doctor give me medicine to stop my bleeding but it never stop...than the doctor put me on progesterone....but my bleeding never stop..my bleeding only stop after i take norethistrone but after i stop take norethistrone my period will come after 2 or 3 days....i don t know whats my problem...