Chemical or miscarriage?

With my first kid it took into the 6th week to get and hpt, I just had low HCG levels. Last month my period was 6 days late with BFN's. I also passed a clot that was the size of a quarter and was (TMI) Bloody, fleshy colored, and purplish. I've heard it's very common to get pregnant the next month. My period is expected in two days but the real thing I'm getting at here is how many of you has this happened to where you were pregnant the next month?