Vanishing Twin at 6w1d

Just found out we lost one of our di/di twins at 6w1d. I had bright red blood and spotting with no cramping twice last week. The other baby is advancing at 8w4d. It was heartbreaking to see because the surviving twin has a heartbeat of 170, little arm and leg nubs, and a growing umbilical cord. The other baby hadn’t grown since 6w1d and we saw it pulsating but it was from my own heartbeat :( was devastating. They were both measuring the exact same 2 weeks ago. I can’t help but blame myself and try to think of any little thing I could have done to have caused this.

I’m so terrified to lose the other baby now. Has anyone lost both twins at different weeks or do most people go on to have the 2nd baby?

I feel so much for parents who lose one child and I feel lucky to still be currently pregnant with one. Just hoping s/he sticks around with me. Then after reading about vanishing twins, research is showing there could be issues with the surviving twin. Such sad news all around :(