Bleeding with twins

I’m 6 weeks with twins, had a scan last week due to spotting which is when they found 2 sacks. Went back yesterday as bleeding red blood and a couple of clots, no stomach pain though. Sonographer advised baby hadn’t grown and I was having a miscarriage, they could only find 1 sack though . I’m now today bleeding a small amount of red blood and still no cramps is it possible they could of missed the other sack? I know I prop sound like I’m going mad but I still have no pains? Could there be a mistake? Xxxx