Confused?

Me and my husband have been trying to conceive for a few months already. And no luck. Yesterday when i was changing into my pjs i noticed that my nipples are very dark and have white spots on them. I already have a 2 year old and i didnt have no symptoms at all with her, so now i am confused what could this be? And i am also scared. My period isnt due until the 13th of this month. We always have unprotected sex. Can i get some help plz?