What Are The Side Effects Of Norethisterone?

I have a history of hyperplasia. I ve had d&c s done, biopsies and for years have been taking norethisterone 5mg days 13 and 24 of my cycle. I am 46 and the doctor suggested to stop with pills and try go on without them. My cycle went crazy after that. Two months period didn t come and now I won t stop bleeding. First 8 days were heavy, then bleeding tapered off. Stopped for 4 days, and now is showing again for past 6 days. It feels like a continual period. After 8th day I started taking norethisterone, didn t wait until 12th/13th day in the hope it would stop bleeding. As I said, stopped for 4 days, but now it s back. I guess my question is, when/how do I keep taking these pills? As I said, I started taking them on 8th day of period and took them for 12 days. But there s still bleeding(light but dark)--should I continue taking them for another 12 days?