I've noticed my boobs have been tender and sometimes they get an aching feeling

The last couple weeks I've noticed my boobs have been tender and sometimes they get an aching feeling . My nipples have also gotten darker like a dark brownish purplish color and I can notice a not as dark line around the areola like a ring around my nipple , not to mention I do feel nauseous from time to time for short periods at a time throughout the day . I dont believe I had a period this month and I could be a week late that happens sometimes . I'm not sure if this is normal because my body could be changing or if it could possibly mean something else , plz share your suggestions ! thanks .