You will know you have thrush if you have a burning sensation and an itch down below . Sometimes it can start in the mouth with a white coating on the tongue but can disappear and leave the tongue looking as if it had been burnt and a little red , also if you drink a lot of sugary drinks and white bread it can cause this to happen . Its a yeast infection and can be treated no problem but it is very uncomfortable and to be honest I wouldnt recommend sex with your partner if you have it , I have got it on several occasions and never have done , I find I get it when I take antibiotics or eat a lot of white bread so I try to avoid both , bread soda is a quick relief for the itch in the bath with tepid water but is not a cure , go see your doctor,