I had low supply with my first, so bad that I ended up using formula - doctors orders, she was dehydrated - it was scary.
My second was a whole different story - nursing worked out fine (with the usual engorgement, blisters, mastitis, etc ....) . Mother's milk tea is fantastic.
Honestly, I think that stress has a lot to do with milk supply (at least for me) - your efforts to pump before the birth seems exhausting and not useful - just let your milk come in, trust that it will be a different experience the second time, drink the herbal remedies if you need.
I proceeded to have two more babes, and nursing was fine with them too. It was like my body knew what to do the second time around -
also, I was under a lot of stress the first time, and life was very chaotic - the second time was a bit calmer, I was better able to understand what my baby needed and when.
The other thing I did the second time, which I think really really helped, was to have no-one come visit me in the hospital after my second was born (well, my parents came). My husband stayed home with the oldest (who was 2), and I had perfect peace and quiet to pay attention to my second daughter, get to know her, listen when she was hungry, and respond immediately with NO distractions, no feeling uncomfortable with visitors, and waiting to nurse until visitors were gone. Before I had to go home to my first. This was invaluable.
Think back: did you have lots of company the first time?
Did you have lots of visitors at home? Did you ever delay nursing because of this? Was your home life stressful?
That all worked against me, and I made changes the second time around that helped tremendously.