Hello Doctor, I Am 30 Years Old Female. I Have

Hello Doctor, I am 30 years old female. I have been suffering from vaginal infections past 6 years. I used to get boils on both sides of the vaginal lips, kind of ulcer some times and bumps/thrush sometimes. This is happening every month before the period cycle and it becomes worse at the time of my cycle. It gives pain, itching and burning sensation and am suffering a lot. Am not able to sit,walk or sleep. Visited many gynecologist and they say there is no way to prevent this except for a healthy hygiene. I was given doxycycline, metronidazole tablets for a month. I use cotton wears, change pads every 4 hrs, not in a relationship at present. The problem still exists and I suffer a lot. Please suggest me a way to get rid of this. Thank you in advance.