What Causes The Sudden Decrease In Size Of The Breast?

Hi, during the last 3 weeks I have notices my breast have gotten smaller, it is very noticeable, since even my husband has told me. I calculate about 25% smaller. I am diating and excercising, but the rest of my body has not changed and I have not lost any weight. Also all of last week I had morning heartburn, I woke up very hungry and was hungrier than usual, light lower abdomen ccramps, gas and bloating. Today I seem to be fine have not feel any of that.