Disappointed

I feel so sad today, I had my first ultrasound and they saw twins but upon further review one looks like it's not viable and the other has a yolk sac but doesn't have a heartbeat yet. I know it's still early and I should be thankful one of them is looking very good, but I can't help but mourn the loss of the other. After a miscarriage earlier this year I just didn't get any reassurance that this one will stick and I'm just sad now.