What could be wrong if a period comes early and last longer than 10 days?

One-time symptom?: A doctor can check to see if there is a medical issue, if a woman has mild menstrual-related symptoms. Many women have some variation of mucus discharge, of periods, or a missed period on occasion. Some women feel normal after a few days, but others have bothersome symptoms and follow-up with a doctor. A urine pregnancy test is accurate if done correctly, after a missed period, or 3 wks after sex.