Worried

I’m currently 6 weeks pregnant as of today i had had a miscarriage back in August 2018 i was 8 weeks. The last 5 days i been bleeding not to heavy but like a period i went to the ER twice first time my beta level was 409 Second Time They checked my cervix & it was closed also that day i had passed a blood clot in so worried i took a pregnancy test today and it was still positive.... don’t know exactly what’s going on please give me advice. Also the first day i went to the ER I Had an ultrasound & it wasn’t nothing in my uterus ( they didn’t see no sac or anything because i was to early i was 5 weeks & 4 days)