A week ago I had unprotected sex and took plan b one step within the 24 hours. I have been having one nipple be constantly hard and itchy its only been a week. I don't know if it has something to do with my breasts or if I maybe pregnant. I eat day old food from work and I've been having tummy issues since then. I don't know if its from the food or I'm pregnant. My breasts aren't sore and its only the one nipple that itches and stays hard. What could this be?