Possible trigger warning..

How likely is an obvious positive test 12 days after having sex

I had a miscarriage last month. Been 3 weeks 4 days since it started and 13 days since I stopped bleeding.

I got my green end test on Saturday just gone (6 days ago) it’s pretty much negative. Done as the hospital told me to cause my HCG on the 20th sep was 55 so they expected it to be gone by now as 2 days before (18th sept) it was 95 so dropping fast.

Green and purple end test same sensitivity (20)

I took green one on Saturday. Purple one yesterday and the darker first response last night. This morning I did the lighter first response.

I’m so confused as if my test Saturday was pretty much negative how are they now so positive ? But then 12 days after sex seems to soon for such a positive !

I also did a clearblue about an hour ago but the day before I did my green test I got 1-2 on clearblue remaining from miscarriage I stopped bleeding 2 days after that.