breast changes

Okay Ladies, so I'm 19 I'll be 20 in July. Anyways, my breasts about a month ago started going through changes. My mom insisted I take a pregnancy test so I did, but it was negative. Then a few days later my period came. So that's out of the way. Well I'm off my period now and the changes are still there. I thought maybe it was just a period symptom. My nipples have changed greatly. They are now slightly darker and inverted a bit. The little pimple like spots on my areola stand out so much more now. They do feel a bit heavy off and on throughout the day, but they don't hurt. My veins have actually become more prominent as well. I don't know what it could be besides a sign of breast cancer. Have any of you ladies experienced this and been fine?? Anything help. Thanks lovelies.❤️️