Miscarriage? Vanishing twin? PLEASE READ

I found out I was pregnant at 3W2D that night I had some brown/red spotting but NO CLOTS or cramping. But I went to the ER anyway (Saturday night). They did a blood test and ultrasounds confirming pregnancy saying my HCG levels were 541 and that I was around 3 weeks, but to go back Monday night and get another blood test to just see my HCG levels again. I went back (to a different ER) and they said my HCG levels were 473 so they dropped 68. They diagnosed threatened miscarriage and told me to take it easy and make an OBGYN appointment for two weeks out. I know a drop isn’t promising but only 68? Like everyone I’ve been googling nonstop. Could it be possible it started out as twins and that’s what’s causing the drop? I read about vanishing twins and every story seems like mine? I’m having strong pregnancy symptoms still and no cramping. Just spotting. Cervix is still closed. Anything y’all can tell me?