Concerned Sister!!!!!

So I just found out that I'm pregnant. I want to tell everyone but I'm lost on how to tell my sister. She lost her baby in October at 5 months and she really took it hard. Like really really hard. I just don't want to send her into a dark place. Any suggestions on how to go about it.

Update.....

Me and my mother decided that she would tell her because she didn't want to me to see her reaction. She called me right after school and told me she was happy for me and she was excited for me to go through it. I let her ask the question and she was really happy. She asked me why I didn't tell her and I let her know why and she said she understood. So thanks for the comments.