I had a miscarriage 4 weeks ago and I done a pregnancy test last week and it was positive I done another one today and it's still positive very faint but still a clear positive, I've had no period since my miscarriage, I've had unprotected sex 3 times since and done a ovulation test which was a strong positive(don't think I'm pregnant now tho as only had sex 2 weeks ago) why am I still having positive tests?