Sono 5-7 weeks?

Delores

I’m so funused about how far along in my pregnancy I am because when I had a sono last week the doctor was going by the emergency room dates which the er was not that helpful when I went I believe I am 6 weeks now and my sono was done last week to the er and my doctor I am 8 weeks pregnant when I had the sono there was no heartbeat but a flutter/small movement my hcg levels have risen and declined and risen again any ideas laddies? I’m worried the just because the doctor is questioning weather or not it is a viable pregnancy; maybe a hidden twin or vanishing twin maybe I’m right and I could be 6 weeks this week