Breastfeeding moms I need help!

My son is 5 weeks old and it seems like every time I breastfeed it isn’t enough for him so I have no choice but to feed him Formula because he’s resisting my breast An is clear to me he’s still hungry. I read online feeding him formula can reduce my milk supply because it’s not sending my body the message to produce more milk. What do I do ? I’m not comfortable feeding him formula I want him to be a 100% breastfeed baby. But if I’m not producing enough milk an he’s still hungry the only option I have is formula.