Miscarriage positive HCG 3 weeks later

I became pregnant 3 months ago today. I went for a private scan at 9 weeks, 2 days and was told baby measured 7 weeks, 3 days - and no heartbeat. I was devastated. I had no symptoms at all. I felt and looked pregnant.

I waited it out to pass the baby naturally. 2.5 weeks went by. It was horrible to wait. I was 11 weeks, 6 days. Just when I scheduled for an OB appointment to get a D&C;, my body let go of the baby suddenly. I was told miscarriage takes hours. I passed the baby in 20 or so minutes, start to finish. It was so fast that I blacked out and my husband called 911. I wasn’t in pain. Just tons of pressure every few minutes and I’d pass clots. I passed the gestational sac (the size of my palm) before the medics took me to the ER. I stabilized, got fluids, and was sent home. We searched and found the baby. It was wonderful and so sad. We were told my scans were perfect: perfect baby.

Now I’m 3 weeks past the full miscarriage. I had an appointment a week ago and was told it seems I’m past it all - but they didn’t do an ultrasound or blood-work. The doctor didn’t even look at my photos of the miscarriage. Just a cervical check and questions.

I keep spotting very faintly every day about once - super light pink/brown. I had EWCM with brown one day and today bright red in EWCM. I feel a bit crampy again. But I’m still testing very positive on a FRER. So it can’t be ovulation yet.

How long does spotting and positive tests usually last?