At 6 weeks pregnant I had bleeding so I called my GP and he booked for the same day an early pregnancy scan, and I saw the heartbeat everything was fine, you should do the same.
I think is more likely that you still fell pregnant, the hormones take a while to leave the women body, a friend of mine did a oregnancy test 2 weeks after miscarriage and came positive, thinking she was pregnant again but scan showed nothing there, so, go for a scan!
I wish you all the best!