Coping with the loss of a twin after birth
If one of your twins dies before, during or shortly after birth, you are understandably going to go through a huge range of emotions and upheaval. Whether or not you were prepared for the loss of one of your babies or if it was totally unexpected, you will be in an entirely bitter-sweet situation, with one newborn to love and nurture, and one to grieve for.
Although no one will totally understand the individual grief and heartache that will be personal to you and your partner, or how you as a couple will cope with the awful situation you find yourselves in, there are organisations who will try and help you through it. SANDS (stillbirth and neonatal death charity) and TAMBA (twins and multiple births association) both have helplines you can call and literature you can download from their websites.
Talking about your loss
In the future, it is likely you will want to talk to your remaining twin about their brother or sister. Indeed, such is the complex relationship of twins, they might even grow up to feel an inerrant sense of 'loss' even though they never 'knew' their sibling. With that in mind, if appropriate, you might want to take photographs of your baby, a lock of their hair, or other mementoes to celebrate and remember them by, and for your other child to see in the years to come, too.
You will undoubtedly want to speak to hospital staff about what went wrong with your pregnancy, and why your twin died; to want answers is entirely normal, and medical staff will help you work through this, and give you all the information that they can. You might feel anger, as well as grief, or even blame yourself or others for your baby's loss. Your midwives and later, your health visitor, should also have information about grief counselling, and perhaps local support groups who could help you and your partner deal with, and eventually, in time, come to terms with your baby's passing.