Not filling enough

Does anyone else have a problem with breastmilk not being filling enough for your baby? It seems with us anyway that with breastmilk I have to feed my baby twice as often with the same amount every time. And sometimes even then I have to top her off with formula because she isn’t full. I don’t know if anyone else has this problem but it’s so frustrating! If she’s not getting full why even bother with breastmilk, would she be happier with formula...as much work as it is to pump and try to keep up I’m still having to give her formula so why bother. First time mom here and feeling frustrated and confused on what to do. When she has formula she’s much more content. And as she gets older and eating more it’s gonna be harder and harder to try to keep up, right now I’m barely pumping enough to keep up. I have tried everything to boost my supply but nothing seems to be working.