What Can Cause Swollen Areolas?

Hi. My Areolas are swollen and turned a very light color. Also my nipples hurt. I haunt had my period in over a year due to depo provera. My last shot was in aug. All of my pregnancy tests come out negative but I feel like I'm pregnant. I'm tired all the time and feel nauseous constantly. Also I've been exhausted and have been having heartburn.