Very worried

Sorry for the long post. 
​I went to the ER today because I saw light spotting (small amount that was light red/pink). This was the only spotting I had, it didn't continue, and that was about 8 hours ago. I also haven't been feeling sick, which worried me because I was sick 24/7 with my first pregnancy. The only symptom I really have is needing to pee a lot and feeling sick if I haven't eaten in a while.
​I got a vaginal ultrasound and they said the sac was measuring at 5 weeks 4 days. But going by my last period, it says I should be 6 weeks 4 days. 
​They were unable to detect a heartbeat or fetal pole. From what I've read this is normal if I am 5w4d, but maybe not if I am 6w4d.
​They did a blood test and said my HCG levels were 4292.
​I deal with anxiety already and this is really causing me to worry non stop.