Have you talked with a lactation consultant? Mine was my best friend at different points. I wonder if with all the hard work you are dehydrating yourself. Regarding your nighttime supply, how much nursing are you doing at night? Maybe you should try to pump (or hand-express) a couple of times after the baby goes to bed, just to keep the stimulation going.
We focus so much on losign the baby weight because we think that we have such a small window before it settles on us and becomes the new normal. I guess that's the case for some. Because my weight gain happened the other way around, I'v ehad the luxury of not worrying about it right now. When I got off the pill years ago, I started gaining weight. I couldn't figure out why because there was other stuff going on. When I got pregnant, all that weight went to the baby. I was svelte and energetic (except for when sleep just hit me like a ton of bricks, even when I was driving or sitting at my desk at work) throughout and for a few months after. Then, my hormones "balanced" back out, and the weight came back. Ugh! After two years with no period, it finally came back, and I got a burst of energy. I am convinced that once I stop nursing (baby is 14 months, and I am so far committed to letting him wean himself), I'll start feeling a little more normal. I might even get back on the pill, just to help get myself going. I don't feel helpless, though. I don't feel like I have to be a permanent fatty.
Of course, you do what you have to do to feel good, but I think that you should slow down a little (maybe just some hardcore walking) and just up your calorie and fluid intake. Did you eat any particular way to maintain your calories during pregnancy? If so, try that again. ...And don't forget to take your pre-natal vitamins! Mine say one a day, but two feel so much better.