Kate: you did the best for your baby and told them your worries and they checked her and she was ok at that stage. There was nothing you could have done differently (it only feels that way because now you know the outcome). You couldn't have foreseen what was going to happen to your baby.
Wishing you all the best. I hope you get some good support from family, friends and professionally too as you need it. I hope you will be blessed with a sibling for Ellen soon.