What Causes Severe Cramps During Menstruation?

Thank you for being here to answer our questions! I m having cramps (day 6 of menstruation - heavier now with copper (non-hormone) IUD (placed 5 years ago). I am a 43-year-old, mother of one. Anyway, my cramp pain (rare) is radiating into my upper right leg, and it hurts! Is this normal, or a sign of trouble? Thank you.