Feeling disappointed I'm expecting a boy

I found out I'm having a boy... But I so wanted my little girl to have a sister (I have a sister I'm very close to). I feel terrible, I'm not sure how to get past the negative feelings. I think part of it is I have friends with super rambunctious and hyper boys that are quite aggressive, and I feel like I'll be a terrible mom to that- frustrated all the time. I'm also grieving my daughter not getting that sister.