I have tender swollen nipples, very heavy full breast, viens in breast, and fatigue. what could this be?

HCG vs Prolactin: A few possibilities: 1) pregnancy 2) elevated prolactin which is the hormone that induces lactation 3) premenstrual for 1, get a pregnancy test for home use in your pharmacy, 2 your physician can test for this hormone, particularly if you have a discharge or milk coming out of your nipples, and 3 if you are in the last week before your menses.