Implantation mistaken for period !

Brittni

So I had my d&c; on august 9th. As of 10/14 my hcg was at 7 from my previous pregnancy. So on 10/10 I started spotting after sex , only when I peed. I used a tampon over night that filled , uses a few the next day. Come the 3rd day it was gone ! No spotting Nothing on day 5 I should of been on I had sex and started bleeding during sex but nothing after ! So my period was only like 2 days long. So I took an ovulation test yesterday which was faint , took one today and I could barely see anything at all. Basically completely gone. Does that mean I missed my fertile window or I was already fertile and conceived and thought it was my period ? My tracker says my window starts tomorrow but I started yesterday just to see where I was. I'm really confused ? Please help. First ovulation test was yesterday and faint. Second today and basically not there at all.