ex having baby today 3 weeks before I was supposed to

Today my ex husband and his wife are having their baby girl. I'm so filled with mixed emotions. I have our 2 daughters today while they are In labor. My due date was supposed to be in 3 weeks...November 23rd. I lost my Aubrey Jean on July 9th at 20w 4d. My girls are so excited for a new baby sister. A part of my heart is breaking because I should be 37 weeks right now and taking my baby home on thanksgiving. But a part of me is so incredibly happy for my ex and my daughters. (We have a great co-parenting relationship) my youngest who is 5 seems confused. The last couple of weeks she keeps asking about my baby. She keeps rubbing my tummy saying "sorry you're dead baby" and kissing my tummy. I just don't know how to feel.