Boobs!!!

I'm 6 weeks pregnant now and my boobs have gone massive. They started hurting a week before I was due on then found out I was pregnant everyday since the pains getting worse and they have gone bigger. With my two other pregnancys I didn't get these symtoms I know every pregnancy is different but they feel like when milk comes in after you've gave birth surely they shouldn't be like this has any one got the same problems? Or know if there's s reason behind really sore boobs??