The fading twin

I have been bleeding since a rather strenuous morning at church yesterday ( is that even possible? ) and a shopping trip. More than before. Enough to make me look in detail at the first ultrasound report and research the word subchorionic hematoma a lot. Turns out I have a 3 cm one of those. ( That is if you combine the three  lateral measurements).   It was originally behind twin B and apparently that is causing the bleeding.
Called the on-call doc yesterday who told me to rest and come in this morning for an ultrasound.
The question is - does this affect the babies and if so how? Different reads on this from different people. The verdict is the same from everyone: Nothing to be done just rest and don't go for any strenuous exercise.  ( Does that mean I am excused from church?)
This morning the  ultrasound tech found baby A no problem - we could see the flicker of the heartbeat really clearly and it was doing 116 beats per minute.  Apparently I'm still 6 weeks - last week I was five weeks. She lingered over there doing a lot of measuring while we freaked out and waited impatiently to see baby B. When she finally made it over there ( it's further away from the cervix so more difficult to see) she couldn't find a heartbeat. The only one she picked up was mine - which is way slower than a baby's. I am wondering if that is what the previous ultra-sound tech found before - because it was slow - 80 bpm- mine is usually around 70 though.
We had steeled ourselves for this, but we were disappointed and sad. It's apparently not 100% conclusive because it was hard to see Baby B because of the positioning. But the doctor said it was probably not looking good for Baby B.
In the space of 6 days we had imagined this whole crazy fun life with twins. We had checked out the mothers of multiples website,  wondered how you go shopping with twins in a  store cart that only has one baby seat, talked about strollers, thought about buying  baby books dedicated to raising twins, considered how it would be great that they would have each other and would not feel alone in their strange but loving origins,  thought about how we would help each of them differentiate so they wouldn't be treated as a unit but as individuals, pondered the stories I would tell them about being a twin myself. And so on.
In some ways it's a tiny relief. Susan doesn't have to worry so much about the impact of twins on my 42 yr old body, we don't have to wonder how we are going to feed two babies, diaper them and get them asleep at the same time, I can have a nurse midwife at the birth and don't have to worry about getting an OB. I'm sure we would have figured it out somehow though.
Our family will be smaller  than our grand plans, and we will have to figure out at a later date how feasible another frozen embryo transfer will be.
So yes, my mind has been incredibly busy. I caught up pretty quickly with Susan's practical bent hence the musings above.
We still don't know how baby A is going to do, although s/he does look good, strong, feisty.
Praying really really hard  that baby A makes it.   We are so lucky to have this baby, we know that. We just want a happy ending. Who doesn't?