My sister had a miscarriage

A couple years ago my sister was pregnant. She ended up losing the baby at about 6 weeks. She was talking about how terrified she was about losing her baby during her last pregnancy(he's 8 months now). I was there for her throughout the whole time during the miscarriage. I even helped her bf bury what she had passed. It was so heartbreaking. But I feel like I can't talk about my infertility issues because she doesn't want me to get pregnant. I've been ttc for 18 months and even though I don't ever wanna feel what she felt, I felt like its unfair that she could even make a baby and I can't. This journey is tearing me apart