Hcg levels

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When I was told there was a 95% chance I was miscarrying at 4 weeks, my hcg levels were 12 (equivalent to being 1 week pregnant). A week later they wanted to retest to see where they sat. .........12. They didn't budge.  No doubling to show I had a viable pregnancy, no dropping to show I was  miscarrying. 
My doc was a bit baffled. Or at least acted that way. Maybe they do that so we as worry warts already, don't freak out? Has anyone else had this happen? The only thing I can think of is my body hasn't passed everything. I'm hardly bleeding anymore and bled for a little over a week. Mostly brown. Bright red at first. 
I have more blood work next Tuesday. Three weeks worth of bloodwork. Already over it. Ready to start trying again. But also hope for some sort of answers. 
Thanks in advance❤️
Baby dust to all✨