Heartbroken about baby b

So I went in for a scan at 5w 6d for fluids due to being so sick and dehydrated and they did a scan... they saw one baby measuring right on target and then surprise there was another one baby b measuring roughly 2 days behind (in the same g sac) I couldn’t believe what I was seeing and had a whole mix of emotions. Jump ahead 5 days I went in to my ob for another scan at 6w 4d and they saw both of them but could only get a heartbeat on baby a and baby b only had a yolk sac no fetal pole no heartbeat. My doctor came in and told me that she believes baby b is not viable and won’t make it and I have another scan on 6/18 to make sure baby b absorbs and doesn’t cause any problems for baby a and I’m so devastated! I know I should be happy that baby a is doing great but I feel like I’ve lost a part of me!