went to the ER last night for spotting..😕😕

So late afternoon I had some bleeding that was like a medium red it freaked me out and i went to the emergency room right away they look my bloods levels and gave me a vaginal ultrasound.. so my levels doubled again and are at 38,000 which is good but when they did my ultrasound they saw the yolk sak but no baby.. they said the sak was measuring about 6 weeks 6 days.. shouldn't there be a fetal pole at that point?! I'm really scared now I'm no longer spotting and when they checked my cervix last night it was closed but no fetal pole at almost 7 weeks? I'm just assuming that I'm super early and that's why but has this happened to anyone else and a week later they see something? Please let me know so I can stop freaking myself out.