Dear Ma'am Hello. Very Good evening. I'm Dr.Yogesh Kr Sharma. For what disease, you are taking Tab. Clindamycin. Seriously I don't know. For pelvic inflammatory disease or any vulvovaginitis ( infection of external and Internal part of Vagina),  Clindamycin is seldom used. Despite having Clindamycin, you have severe abdominal Pain, it means the given antibiotic prescribed by your Doctor is not working. So now the time comes to change the medicines. Also I advice you to go for Ultrasound Whole abdomen to Rule out any lower intraabdominal pathology. For Pain, you can take Tab.  Meftal Spas, one tablet as required or for Pain you can also have Hyocimax -S CR (0.375 mg)  once a day, that would be convenient. Kindly come to practo chat for your change of treatment part until the Ultrasound report comes. Regards.