My identical baby girls

I Went for my detailed ultrasound 3 weeks ago and they saw some concerning things with both Baby A and Baby B. I went to my follow up appointment on Wed and baby A didn’t have a heartbeat any more and baby b is doing ok as of now. I’m 21 weeks and I’m extremely heartbroken. It’s so hard to grieve the loss of one of my girls but be happy for my other girl. It’s mentally and emotionally confusing. I had so many dreams and plans with both of my girls.