Possible miscarriage but no period & bfp’s

On Jan 29th I found out I was pregnant and it was confirmed with a blood test the following day. Feb 2nd I had another blood test and my levels went from 203 to 138. On feb 12th after no bleeding/cramping I took a home test and it came up positive. I’ve taken two more pee tests since then and all are still positive. With my previous miscarriages they’ve happened immediately. Tomorrow I have an ultrasound to see what’s happening, but I just want to hear if this has happened to anyone else. My midwife said I shouldn’t be testing positive on a urine test anymore, but I am 🤷🏼‍♀️