Due to sevista 30 mg which I was taking for breast cyst. My periods get delayed. I took meprate but periods does not come even after 13 days. Dr. asked me to do ultrasound of lower abdomen. A very small follicular cyst is detected in that. And endometrium thickness is 0.8 mm. I do nt have any periods yet. Dr. given me tab regestrone and panic to take for 14 days. Your views will be really valuable to me. And will these medicine can cause any side effects like sevista does to me. Please help me. I am really afraid of taking any tablets because of what sevista does to me. Please help me. And elaborate.