Monther-in-law issues

Okay so I strictly breastfeed and ive never liked pumping because of how sore it makes me. My mother in law waits till the day before she wants to get the baby for the weekend before she lets us know she wants him & thats not nearly enough time for me to pump enough and still have enough for my baby to get full off of. We always tell her to tell us 3 or 4 days ahead but she never does then she gets pissed like we are keeping her away from him. She seems to gets because I breastfeed and doesnt see why I cant just formula feed. Does anyone agree shes being very rediculous?! 😡