pregnancy boobs

Ladies! I am due my period Sunday (i have 28-32 cycle), and recently i've had nausea every day along with a headache, but now i've noticed my boobs are getting a little sore. It's not all the time, just when they're touched. Its underneath and at the sides. I've never been pregnant before, just want to know what you ladies have experienced in terms of distinguishing pms aches with pregnancy aches? Its driving me nuts