Feeling extremely guilty

My husband I just found out that we were expected and the same day I found out my sister had lost her baby. I feel like I can't be happy about my baby because it would take away from her loss. How can I make her feel better? I feel so unbelievably guilty. This should be one of the happiest times of my life but my sisters in so much pain I feel like I would just be rubbing my happiness in her pain. I want to be there for her but when she finds out I will be the last person she will want around.