chemical pregnancy bleeding

I bled for 3 days, 2 were like a normal period just brighter more red blood then the 3rd day was just spotting. There has been no blood at all in almost a week and now I have black clot looking things coming out of me. No blood or spotting just the black clot looking things when I wipe. My lower back is still achy but I never experienced any cramping in my pelvis not even my normal period cramping. Is this normal for a chemical? I also have really bubbly and gassy feelings in my abdomen.