7 weeks 2 days symptoms fading

I have established both babies have a heartbeat at 6 weeks. And I have had few symptoms throughout pregnancy, lately I have noticed one of my main symptoms is starting to fade. At first I thought maybe I’m just getting used to being pregnant but now I can see they are fading. I know symptoms come and go but I figured with Twins this wouldn’t be the case but maybe my symptoms would have got stronger in time not weaker. I’m just concerned!! I have an 8 week ultrasound on Thursday.

Worst case scenario, what are the chances of me losing both babies?