What could severe lower abdominal and lower back pain with extreme mood changes and heavy bleeding during menstrual cycle be?

Endometriosis? C MD: Dysmenorrhea (painful periods), dysfunctional uterine bleeding (abnormal bleeding during menses), dysphoric syndrome (severe mood changes); could be hormonal. Could be endometriosis (abnormal deposition of uterine tissue outside the inner lining of uterus; hormonally sensitive, painful. Could be uterine polyp, fibroid, or mass. If rectal bleed, then poss infl bowel, ca. See your doc.

Endometriosis: There are a few possibilities. The most common one would be endometriosis.