hi, I am suffering from uterus infection for last 8 months. infection started after 4 th day of each period. PAP and HPV dna test are negative and BV, Fungal infection and high vah swab was negative but each period I'm getting vaginal pain, itchy, severe lower abdominal pain, back pain, knee pain, anal burning and pain when urination. this symptoms disappear after 7 days course of doxycycline and metrogyl.. my doctor said the medicine start itself for first day of period. so i can follow the medicine from my first day of period itslef now my symptoms all clear. but after stopped the medicine again the symptoms are started. all type ultrasound done. nothing is there.