TW friend’s baby is living

My best friend is giving birth via cesarean tonight. I’m not sure exactly how to be supportive and not seem jealous or like I’m not happy for her. We were pregnant at the same time, our girls were going to be five months apart and we knew they would be besties like us. But my girl was born sleeping, we didn’t know she was gone until 39 weeks at our scheduled c. She was gone within the 48 hours before she was supposed to arrive. It’s not fair. I’ve been excited to be supporting her through this, to meet my new niece. But now she’s almost here, my heart hurts so much in mourning for my Winona. My partner and I are so fortunate to be among the few people she’s allowing at the hospital. How do I get through this pain so I can be there for her like she deserves? She was there for me on the worst day of my life, I want to be there for the best day of hers. What mantras help you to get through the heavy times? I would love some guidance with this, mamas.