Selfish or not?

So I recently found out that my sister is pregnant. It did make me upset. But I’m not close with any of my sisters so most people says it shouldn’t bother me. But I had 2 children, both preterm labor. It’s already been a year since I had my 1st son. It will be a year on Feb 21 that I had my 2nd son, which is also the day after my sister who is pregnant,birthday. And she was also my triage nurse when I was in the hospital miscarrying with him. So I was a lil hurt that she made me the very last person that she told, all of my family knew, she said she was trying to protect my feelings. But I would have been hurt either way because my heart still hurts for both my sons. I just feel like it’s all happening so fast. I’m still grieving & everyone just expects me to be okay with everything. My mom even told me that I had to get over my kids death or I will never heal. But how do you just get over it? I love my mom, but I just have a lil resentment with her because when I told her about my 2nd pregnancy, she had nothing positive to say, only that I shouldn’t expect this baby to survive because of what happened with my 1st child. That hurt me! You don’t expect that from your mom. But is it selfish of me to be a lil upset with my sister for getting pregnant on purpose? I mean I’m kind of happy for her but I’m kind of not. I just need advice. And maybe some words of wisdom.