Exclusively pumping but...

thinking about putting my son back on the boob. He's 12 days old, and I started pumping after becoming so fatigued in the hospital that my supply dropped. We had to end up supplementing some formula. He latches great, but is so impatient with the let down. He gets so mad and frustrated with it. I wouldn't mind exclusively pumping, but almost everytime I hold him he still tries to latch on. Makes me think he wants the connection just as much as I do. Another reason I would like to try again, is because each pumping session I'm doing between 3-4 oz (left & right combined, usually 20 minutes). Is this good? Not enough? Should I try some lactation supplements? I try to stay hydrated, eat & sleep well, etc. Any help is greatly appreciated! I want to get this right so bad. None of my family has ever breastfed, and I have two friends who made themselves sound like dairy cows. I feel little inadequate in comparison 😔