From experience, i really don't understand why they scan this early. I think it just causes more worry, at an already worrying time. I think it is more important that you HCG levels are rising at an appropriate level, which yours seem to be. I think your doctor was completely out of order! We all know that seeing nothing at 5 weeks is normal and we are not qualified medical professionals! As i said, i saw nothing with my daughter at 5 weeks and went on to have a perfectly healthy pregnancy and a 9lb 6oz baby at the end. Ask for a second opinion if i were you.