When Will My Menses Return After A Miscarriage?

Hi, I would like to know how long it takes for my period to return after having miscarried 4 weeks ago. I was 10 weeks pregnant but foetus stopped growing at 6 weeks. They apparently said i have completely miscarried after an ultra sound but i got a 2 weeks positive digital pregnancy test. What does that mean? I have no pains and I am not bleeding. Have i still got some tissue left inside me since i miscarried naturally? Your help on this will be appreciated. Thanks 'S'