randnmom,
I SO get where you're coming from. I've never carried a baby to term either, and some days I think my body hates me. I've been pumping a little longer than you, but I'm getting only about 3 ounces on a good day. The thought of not being able to produce enough is devastating to me.
BUT, here's how I've been thinking about it to cut down on some of the stress: When the baby first arrives, he won't want but a tiny bit of milk. All new moms start out with only little supplies. Then, as he wants more, hopefully my body will keep up with his demand. After all, once he's actually here, I should have better luck with supply. And if I do fall behind at some point, I have all those piddly little 3 ounces I've been putting away while getting ready for him.