Ok I need some help ladies...went to the ER & pos pregnancy tests

Cassie
Took this today...went to the ER last night & they said I'm pregnant....but my hcg is low & they couldn't pick NOTHING up on the ultrasound.....saying I have to wait 72 hours....it could go down or up which if it doubles its good of course...but if it goes down then I had a miscarriage...I'm so confused & heartbroken....tell me what y'all think?? First pregnancy😰