does this make me a horrible sister?

I'm a mother of two, but I lost a baby about 3 years ago and I've wanted to try again ever since. I didn't try again until about a year ago because after losing the baby, my husband and I divorced so the timing wasn't right. I got engaged about a year ago and we decided to try because we both desperately wanted another baby. My sister started trying around the same time and got pregnant immediately. I have not. I'm still ttc. She had the baby recently and I just can't find it in me to be happy for her. I can't even bring myself to hold the baby. I feel horrible. I haven't been to visit her because of this reason. It's just easier to steer clear. Does this make me a bad sister?