My husband doesn't know & I feel so guilty

I dont think I'm producing enough milk for my 5week old. After maybe 10mins he stays latched on but will grunt over and over and pull my nipple from side to side and start crying like he isnt satisfied enough. I'll burp him then latch him on other breast and he does the same thing. He cries his "neh" hunger cry and searches for my boob if I try to take him off Soooo... i supplemented half pumped breastmilk and half formula.. my husband is totally against formula and when I've brought it up before he insists I better not feed him any, because he bought me an expensive pump and expects me to make it happen.. he doesn't know I gave our baby formula but baby is so content, full and sleeping well. I'll feel like a failure if he finds out, because he'll see me like I couldn't do it..Personally I rather my baby be fed than hungry regardless how I do it or what I give him.. but i do feel kinda bad I broke my " breastfed only" goal 😔

breastfeeding is hard. I'm still drinking water and pumping to store when I pump enough.. besides water how can I produce more with pumping? Any advice? I'm feeling so sad right now.. I dont like keeping things from my husband either.. I feel wrong