Can you get pregnant with thick lining after miscarriage?

I actually had baby on October 22nd due to taking the pill after baby had no heartbeat at 11 week check up. I’ve been bleeding lightly with clots ever since with one week of nothing. I just had a ultrasound Friday n my lining is still there . I asked the obgyn could I get pregnant she said I could . But on line pregnancy test I’m still getting a positive and on digital it says NOT PREGNANT. Just wondering if anyone ever gotten pregnant with all this going on?

Here is my ultrasound from Friday ⬆️