BabyJo - Im sorry that this is such a hard and confusing time for you right now. If it helps to ease your mind a very close friend of mine had an u/s at 7 weeks and nothing was detected no sac or anything and levels were increasing but not as much as considered "normal" she is now 7 months pregnant with a healthy baby boy so try not to think this is goodbye as it may not be. i hope you get some answers very soon.