I think you should be the bigger one and be happy for her,you don't want to start things out this early in the baby's life, it will grow, and it will be a part of the family and will feel your pain if you show the baby hurt feelings when its born and grows into a human being, and a kid. There is a huge possibility you will have kids soon too if you get back on track with your job and such. You need to give your sister the love for her and her baby she probably craves even though you wish it was you. My sister died an you never know you may need her in a loving way in the future especially dealing with family concerns. I'll pray for you!