Slow heart beat

Hi I was wondering if anyone else is in the same boat 2 weeks ago I bled then had nothing until 2 days ago I spotted Brown blood only for a few hours but the camps I got yesterday concerned me so had a scan and I'm 8 weeks from last menstrual cycle but baby was sizing at 6 weeks but my indicator pregnancy test said I should be 6 weeks but the other thing is my baby's Heart beat is slow I was wondering has anyone else baby had a low heart beat but survived full term I've had an ectopic then miscarriage in January I want this baby and don't want to believe I'm loosing another one I've had no cramps today and no more bleeding can anyone help my next scans in 9 days and don't want to wait that long to think everything could be okay x