Trying to be happy about it but...

So recently me and my sister have joked about ttc at the same time. Two days ago we both took tests and hers was positive but of course mine was a BFN. I wanted to and still want to be happy for her but I find myself giving her an attitude or being negative about the situation without realizing I’m acting like that. She also isn’t too happy about having another baby which makes this situation even more unfair in my eyes. I just don’t know how to control my emotions on it😓