You've just come off anti biotics so it sounds like they've killed off all your natural (good bacteria) defences.
From personal experience, especially when the Canesten treatments didnt even seem to touch it, I'd take acidophilus capsules. I think they come in different strengths. Naturally, I went for the highest strength.
Tips: DO NOT take the acidophilus with a warm / hot drink. Apparently, this kills the good bacteria.
Sugar feeds the harmful bacteria. Also consider sugars in high carb type foods (cakes, donuts, white bread, etc)
I like the recommendations of tampons dipped in natural, live yoghurt. But go to a health shop and get natural tampons - not the mass produced types which are bleached and also leave residual material from the tampons inside you.
Also, get natural material pads. Mass produced popular sanitary ware contains a lot of ingredients that aggravate our bodies.
Shorter term: Ruling out an STD is not a bad idea, if there is any possibility of this.
Longer term, when the burning has subsided, consider vaginal / yoni steaming, which involves natural herbs.
Get well soon!