3rd trimester boob changes??

In the first and second trimester my boobs grew a TON! I am about 33 weeks now and it seems like they have shrunk back to almost my normal size and they are sore again like in the beginning. I was laying on my exercise ball trying to stretch out my back and it felt like I had a big rock in each one. I thought it was just me, thinking maybe they just seemed smaller because everything else is HUGE but my husband noticed also. Has this happened to anyone else? I figured it was just normal changes with hormones and getting ready to make milk but I wasn't expecting it