Vaginal Infection

Make sure proper hygiene is in place, also make sure your partner practice proper hygiene.

Make sure to avoid tampons till the infection is cleared. 

Commercial sanitary pads and tampons are made from very short strands of cotton, these often get "implanted" in your skin, and causes a sensation of "thrush" - Chance to a brand that uses organic cotton like Masmi

Make sure your gut health is in place - and cut sugar from your diet until you are better.