4months PP too late to increase milk??

Betty
I have struggled with my supply since the beginning. I have to actively keep my supply up everyday with things like tea, fenugreek pills, power pumping, baby on breast all day, steel cut oats etc. if I skip a day, my milk goes down. Baby nurses every hour because I can't fill him up in one sitting. I still supplemented 4oz of formula in the evening because baby would cry his head off with hunger. When I pump I get about half an oz combined, 1oz if we skipped a feeding. It has been a real struggle, but I want my baby to have breast milk so I refuse to give up. My day revolves around my milk supply. 
I had surgery two weeks ago and baby had to have formula for a day because of the anesthesia. I refused painkillers because I wanted to get back to breastfeeding ASAP before my milk took a huge dip. Ever since then I had to supplement 8oz a day. We've been working hard with constant feeding to up it and nothing. Until I remembered it's been said that placenta pills can increase milk. Thankfully I had mine encapsulated! I started taking it and on our third day, was the first day we didn't supplement since baby was three days old! I'm so excited. We'll see how today goes. 
Now, my question: I pumped and I still get an oz or less. I really want to have milk stashed for when I can't be around because I don't want to go back to formula. Has anyone had success this late in the game with increased milk to the point of having enough to stash? Thank you!