Cluster feeding but not enough supply??

So when baby cluster feeds I noticed he’s getting frustrated cause my supply is getting low. As soon as I give him like an extra ounce of breastmilk in a bottle he’s out like a light! So clearly he was just missing that extra ounce. I know this is all supposed to make my supply go up but how long do I make him fuss like that until he’s satisfied if there’s literally nothing left coming out of my boobs ?? He literally empties them and then some so I just resort to giving him an extra ounce in the bottle to calm him down.

What am I supposed to do if my supply is just not there to fuel his cluster feedings ?? I’m confused.