I had a period that was very heavy and I went to see a doctor who prescribed norethisterone tablets for 10 days the period stopped for a day and then continued with clots the scan reviewed that I had thick lining uterus and the doctor wanted to do endoscope op which I'm waiting for the appointment but after 10days I stopped the tablets and the period stopped after five days and I had unprotected sex two days after and again8days later I have not had a period and I feel nausea ,heaches , peeind a lot I did pregnancy test it came back negative what could be causing these symptoms please