Very confused mom of 2

Hi Ladies !! I was wondering if maybe someone could help ?  My last menstrual was June 1 I've been expecting my period but it never came I've always been a little irregular anywhere from 28-30 days .  I've been taking test but they say negative I started spotting last night but it's gotten heavier overnight  . I've got sore breasts and feel very fatigued .  Guess I'm just curious if some heavy bleeding is common with implantation or if this could just be a super late period ?? Has anyone experienced this ?