What are the chances of another mmc?

I had a mmc in september at 6w. My baby had stopped growing at 4w.

I got pregnant straight away, and paid for a private scan. I was dated at 5w5d, and we saw the heartbeat.

Today i am 8w3d, and have had no symptoms for a few days.

No nausea, no food aversions, no sore boobs, no stretching pains or cramps.

I am making myself sick with worry that it will be another mmc?

My scan is 18th december, and i know it will destroy this christmas if its a mmc :(

Advice please?