Thanx mommyd2012 u answered my question.
I'm 6wks and that is how I felt around that time....my breast felt both heavier and plumper....walked around for days asking the hubby if they looked bigger.....slowely began yo feel queasy that is when I knew I was pregnant! It is normal your belly hardens and feels stuffed when the uterus changes to host the baby....also if your breast heaviness is still a problem wear a sport bra to bed at night....also invest in a good support bra to wear during the day.....this made the world of a difference for me.....good luck!
Don't worry, it's all normal. We all feel different when we're pregnant. Some people have little or no symptoms, others have a lot. It's also very different one pregnancy to the other. Make sure you're getting enough vitamins (take Maternal supplements if you're not already) You should feel better by the 2nd trimester.
Oh and another thing my breast feel so much heavier ..