Help I don't k ow what to do!!!!!!

I am a bridesmaid for my sister in laws wedding. She is getting married in September. My daughter is 6 months old and only breastfed. I have been going crazy. She won't take a bottle of formula or breastmilk at all. I even thought about stopping breastfeeding her and getting her on formula. My mother in law is constantly asking me "what are you gonna do with the baby for the wedding?" Pretty much asking what am I gonna do if she starts to cry during the ceremony. My sister in law has a party bus for after the ceremony. She has the bus for 4 hours and says no kids allowed on the bus. So then I ask her if I can pump on the bus and she says "ew gross". This is why I have been thinking about just getting my daughter off my breast. But now I'm just like F this! I was 9 months pregnant when she asked me to be a bridesmaid. My baby will only be 7 months old at the time of the wedding and she is gonna need me. If she gets hungry during the ceremony then I'm gonna leave my place and go and feed her and if I can't take her on the bus or even pump on the bus then I jus wont go on the damn bus!!!! Ugh what should I do? What would you do?