Implantation bleeding? TMI TMI!!!!

I'm sorry I didn't know how to do the TMI sticker. My last period was 11 July. I'm not irregular so my next was due 8 Aug. I started spitting yesterday I thought it was AF except I didnt even filled up a panty liner. This is all I get. When AF comes I get a big flow (sorry TMI) but enough that if I'm by prepared my panty is drenched.  Has anyone had implantation bleeding before? Could this be it? I'm so confused i have slight cramps keeps feeling like AF is just gonna drop but nothing! I've never had my period a week earlyj