ER doctors are trained in triage of emergency cases, emergency life-saving techniques, and deciding what people who come in with problems should be admitted to the hospital. An ER is a lousy place to get thoughtful analysis and careful discussion of the status of an early pregnancy. If your hCG numbers are doubling, take that as evidence that all is going OK. See your own ob-gyn and things will probably be looking up. Good luck!
Well, OK, lousy was too strong a word; I've had good ER doctors even when the issue was gynecological, and they will even call in an ob-gyn if it gets past their expertise. But I would not take an ER doctor's opinion about an early pregnancy issue over an ob-gyn's opinion about it.
I had ultrasound and was told 5 wk 4 d and same thing as you by ultrasound tech but I spoke to my obgyn the next day and he said do not panick that still very early in pregnancy doing a repeat scan in ten days and see if anything changed. So there's a chance you are just to soon to see anything.