Do you think your BV/Thrush/UTI is triggered by your period, or sex? Try to think if it corresponds with that
For a while, condoms when having sex. Preferably latex-free
Wash with Aqueous cream only. Drink 2 teaspoons of Apple Cider Vinegar in a glass of water (the one with the 'Mother' in it only), morning and night.
You can wash your vagina with Apple Cider Vinegar too if you're feeling sore. Mix well with water tho or it could burn.
Take a good pro-biotic supplement, make it your daily routine for life.
Eat yoghurt/have yoghurt drinks with 'Lactobacilli' in it (most supermarkets have them) at least 1 a day.
You can also take Goldenseal, it's a good anti-fungal supplement for helping to prevent thrush
STI clinic may suggest putting you on a 6 month course of treatment to hopefully solve things, although I guess there's no guarantee it will.
Cut down on yeast and sugar in your diet too
It's a case of trying to restore your vagina's pH balance really, to hopefully prevent bacteria and infections taking hold. I went thru similar in my 20s and followed above system religiously, and it helped. Although I didn't get UTIs
Separately though it would be a good idea to ask your GP to look into why you get recurrent UTIs. I'd have thought they'd be looking into this particular aspect already?
I'm sure someone will be along with more info soon