Supply question

Rachel
Hey ladies, quick question. My little guy is just about 3 weeks old. I am EBF and pumped a bunch the first week to not be so engorged and have a pretty good amount stored up. Everything started to even out, so I didn't pump the past two weeks. Now I'm at the point where I want to pump to get a good supply built up for when I return to work. I'm feeding him pretty much every 3 hours like clockwork, sometimes 4. I fed him earlier today from both sides and then went to pump afterwards. I only ended up getting 1/2 an ounce from both sides together! I was so sad! Any opinions on if my supply is low or if I'm making just enough for baby and not more? He is definitely satisfied and has plenty of wet/dirty diapers so I'm not worried about that. Just want to make sure I can pump enough! Any thoughts/comments are appreciated! Thank you!