I’m confused... someone help me out please...

Tiffany

So I’m 7dpo..... my boobs are really sore and have been for about 3 days. I think I’ve been cramping but I’m not sure. My period is due in about 6 days.... what I’m confused about is.... if implantation doesn’t usually occur until like 9 dpo.... sore boobs before that would most likely mean not pregnant.... right? Because you wouldn’t have symptoms of pregnancy until after you’ve implanted....? Correct?