breastfeeding in unsupportive house

How do you manage when everyone tells you just give your baby formula? or tries to explain to you that breast milk is not as good for baby as formula? when your baby is going through a growth spurt so they try to use it as proof that your baby is not getting enough from breastmilk? i cant stop crying like everything is perfect she latches well my milk came in quick and now shes going through a growth spurt so super cranky and constantly hungry and feeding if shes not sleep.