Boyfriend's sister is pregnant..

My boyfriend's sister made it Facebook official she was having baby #2 with her husband. It's awesome they're finally having another baby but it makes me sad because my pregnancy was dramatic and when I was in the hospital I was alone and I cried the last day and a week after. I wish I could be happier for her but I just can't. And her baby will be here when my LO is 7 months and that makes me feel bad because I'm not ready for him to get bigger. :(

Is this wrong of me?