How To Treat Sticky And Smelly Vaginal Discharge?

I am 23 years old, weigh 75kgs and am 1.6m tall. I have been treated for bv before. My Problem: I have terrible smell of strong ammonia left on my underwear and it is left wet as well with a streak of white. I have very little discharge, it is creamy in colour and very sticky but the discharge itself smells like onion or garlic. I also get an slight itch after washing on the outside of my vagina. What can i do? The smell is very embarrasing and i'm constantly having to wash and change my underwear