Girls, who had it like that and what does it mean? In the first trimes…

Girls, who had it like that and what does it mean? In the first trimester, the breast was straight very big (I have a breast 3-4 sizes in Real) , big such swollen and heavy, sometimes it hurt. Well, in general, as with all. Now 21 weeks and already two weeks the breast just deflated, became even smaller than before and was during pregnancy. Just doesn't hurt at all. What could this be?