vanishing twin syndrome

I had my first scan done about 3 weeks ago when I was 7 weeks and 3 days pregnant. The ultrasound showed up with 2 sacs but only one baby (vanishing twin syndrome). My gp and the lady doing the ultrasound said it was quite common and because I would've lost the twin at about 6 weeks, there isn't anything that needs to be done about it. I'm now 10 weeks and 6 days pregnant and I don't know whether it's even possible but I'm scared that at my next scan (12 week scan) the other twin will have vanished too. I've tried googling and haven't found anything but if anyone here has had a vanishing twin or knows anything about it, I want to know if it's possible for the other to just disappear too? I had no bleeding with the first one so I had no idea I was misscarrying which is what worrys me! Also if you have been through vanishing twin, was your pregnancy normal otherwise and was your other baby okay? I'm feeling so paranoid 😂