I do think stress takes a toll, including sleeplessness. Once E began sleeping longer stretches it evened out for me (although I have the luxury of only one, not juggling 3 !). The thing that made the most difference for me (I also took fenugreek and drank something called "mothers milk tea" daily) was finding the right pump. I had a mega expensive double electric pump for the first few months and it didn't really work to remove much milk, so my supply dropped as soon as I went back to work. I switched to a cheap Avent hand pump and it was like night and day...the lactation consultant who helped me said that after your prolactin levels drop (around 6 months) then mechanical stimulation is the best way to increase, and for me, that meant hand pumping. My hands are a mess now (tendonitis in both wrists and elbows) but it meant I had enough milk for E. If you're only removing 1 ounce then your supply will definitely be restricted.
I know your kids are getting bigger now but maybe the lactation consultant could help with pumping techniques ? If I had my time over again, I'd ask for more help to learn how to pump effectively (induce let-down etc). I only figured it out by trial and (mostly) error.