Hello, You are suffering due to late periods and prolonged spotting. You had ultrasound done and it has confirmed that you are not pregnant either. Hope the ultrasound has also ruled out ectopic pregnancy. Spotting instead of periods may be indicative of PID, PCOS, sexually transmitted diseases that are caused by gonorrhea or chlamydia. These STIs can be treated with antibiotics or antivirals. Both sexual partners should be tested so that they can be treated to avoid re-infection. Very low body weight can impact your hormones, may stop ovulation. This may lead to amenorrhea, late or missed menstrual periods or spotting. Medical conditions like thyroid dysfunction, stress and use of birth control methods / devices can also cause spotting, scanty menses, or irregular menses. Get clinically examined by a gynecologist, get required test & investigations done. Get treated. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician