Late AF after miscarriage.

Had a miscarriage. Bled from 30th Dec-6th Jan. Period is due today and no sign of it. Taken a preg test on 29th Jan which was positive but has been positive since the 21st of Jan and continuously faint and not getting darker. I know I need to see a doctor but what on earth is going on?! Silly mother nature! 😞😭😔