8 weeks what type of scan is needed? help please ladies.

Faye
Had a scan at 6 weeks ( transvaginal)with hospital and heart beat seen, almost 3 weeks later ...I've just been to have a scan privately for reassurance and no baby or yolk sak :( this was abdominal scan only. I'm so worried as had alittle bleeding a few weeks ago. Could it still be too early to see on abdominal scan? Help please xxx