A 26 y.o. woman complains of sudden pains in the bottom of abdomen irradiating to the anus, nausea, giddiness, bloody dark discharges from sexual tracts for one week, the delay of menses for 4 weeks. Signs of the peritoneum irritation are positive. Bimanual examination: borders of the uterus body and its appendages are not determined because of sharp painfullness. The diverticulum and painfullness of the back and dextral fornixes of the vagina are evident. What is the most probable diagnosis?