Hi I see no one has replied yet so I'm going to put my thoughts out there! When I had a miscarriage they followed up every week with a blood test to check my beta's were going down and didnt discharge me till it was 0 and I gave a negative pregnancy result, did this not happen with you?
I was also told that you can ovulate 2 weeks after a miscarriage so it could well be a new pregnancy, go to your doctor and get bloods done, only way to find out, good luck xx