Feeding issues

Edited to say: I try to let baby nurse. I want him to nurse, he refuses.

Can anyone help a mama understand? My baby is breastfed but I guess in the evenings my supply drops or something and he gets really upset and won’t nurse and screams at the breast. I offer A bottle of either breast milk or rarely formula and he will only eat like an ounce and then cries at the bottle and wants to nurse. What is going on😓😓