Hi, I understand your concern. Menstrual pain as you usually have is chractorised by uterine squeezing action, to expel out broken endometrium from un conceived uterus. That is menstruation. This pain usually decreases to disappear as the bleeding stops. This month you have severe pain that increases with pressure on perineal pressure/ associated with fever with chills.. this indicates aggravation of menstrual cramps due to additional cause like endometriosis/ pelvic inflammation, ovarian cyst, uterine fibroid. - You should take rest/ try to sleep on abdomen & apply hot pack on lower abdomen/ take anti inflammatory pills available over the counter after food/ take light food/ drink lot of water. - In case pain/ fever are not controlled / the same pain & complaints remain/ recur, you need investigations like - urine analysis/ high vaginal swab culture & sensitivity test/ USG lower abdomen & some times laproscopy... to pin point the cause. Consultation of a gynecologist for cause specific treatment would help you. Thanks.