How do I say no?

Haylee 🐑
So I'm having a c section the 5th and at first we planned on driving out of state over 15 hours I believe. I didn't think much at first but now it just sounds crazy to do something like that with a newborn! How do I tell my fiancé I don't wanna go. We planned on seeing his family. I also found out his brother doesn't vaccinate their child so I wanna wait probably a while to go see them. How do I tell all of them no? It's definitely not gonna go over well! :(