My baby was cluster feeding for hours, so I made him a bottle of formula because I was worried he was starving

I thought there was no milk left in my breasts, so I made him a bottle and then I pumped. In 10 minutes I pumped 6oz from both sides. That seems like a lot. It’s my first time pumping though so I don’t know. My baby is 2 weeks old.

I also use a nipple shield so I’m wondering if maybe he’s not getting enough milk because of that or because of his shallow latch. Or maybe he is getting enough and he’s just cluster feeding? Maybe I should order a baby scale….