I don't know if I've had it before or not

Hiya girls I'm 3 days late still bfn I have white tipped nipples is this related to my period coking or something else they are proper white not all the time it comes and goes I looked it up and it just said Nipple blanching from breastfeeding I've never breast fed as I'm still trying for my first any advise would be appreciated thank you Xx