Heavy Menstrual Cycle For Approximately Ten Days, No Sign Of

Heavy menstrual cycle for approximately ten days, no sign of decreasing. This has never lasted this long but have been increasingly worsened over the last year. Am experiencing large tissue like discharges, feeling weak and tired, and moderate pain. Not pregnant (no sexual partners for at least two years) and have never been pregnant (no children, miscarriages, etc. -never) Am 41 years old. Should I be concerned? Do I need to go to a doctor? or Is this normal for my age?