What Causes Severe Abdominal Cramps During The Menstrual Cycle?

22-year old female, complaining of severe cramping with her periods; cramping began x 5 years ago but has become worse over the past 6 months, cramping is mainly in her lower abdomen on both sides ,pain to her lower back as well. cramping starts approximately 2 days before the onset of period and last about 2-3 days after her period has started. menstrual cycles are regular, occurring every 30 days and lasting on average between 5-6 days in total. menarche was at age 12. sexually active for the past 3 years , painful intercourse at times. No history of STIs, urinary symptoms, diarrhea, or constipation, extremely fatigued 1-2 weeks before period has abdominal bloating. Dysmenorrhea or endometriosis ?