Breast feeding help!

Rachael

I pump and bottle feed my baby (he’s 6 weeks old) but the problem I’ve been having is he’ll eat 3-3.5 oz and then in 2 hours he’s starving again. My doctor says he should be going 3-4 hours after that amount. It’s taking a toll on me at night because he’s up every 2 hours still to eat. Idk if it’s my milk not filling him up or if I should switch to formula to help fill him up ?