Have you tried inserting tampons soaked in coconut oil? Coconut oil is antifungal so this may help. Alternatively many people suggest yoghurt covered tampons, these never really worked for me but may for some people.
I’m sure you do everything else I do, wear cotton knickers, sleep without knickers, use non scented shower gels.
Taking oral probiotics should help however the capsules are expensive so you might want to consider making kefir which is cheap to make and strongly probiotic.
Hope this helps, i know how horrible they can be.