I'd never heard of this before but I googled "heavy breasts after early period" because my breasts are getting heavy and I'm having twinges in my lower abdomen. My period was 5 days early but the bleeding was too heavy to be implantation bleeding.

The first time I was pregnant, when they tested it turns out I was a month further along than I thought. I'd had what I thought was a regular period in May.

http://www.women-info.com/en/decidual-bleeding/

Maybe I'm grasping at straws because I need to have hope but nonetheless this was interesting to find out.