Pumping but need to start topping with Formula

N.

I’ve been pumping and giving and it was working really well, I was happy and baby was well fed. My supply overnight went down and baby’s appetite went up. Although there’s nothing wrong with formula I actually am feeling bad I need to start topping up but a well fed baby is the most important. I don’t know why I feel like I’ve failed as a mama 😢 But at the same time I feel I’ll be happier once this feeling goes cause he’ll be less crankier and fuller.