I'm also finding that the 2nd pregnancy is so much more demanding than the first - just because the entire daytime is spent focused on the first child, there's no time for me to look after myself. My back is killing, we just moved house, our helper won't be here til the end of the month, trying to get our first daughter into a big girl bed requires soooo much effort... we've been having to watch her and keep putting her back into bed. It's pretty intense - although I know from experience that as tough as pregnancy can seem, it's only gonna be harder once the bub is born!!! I can definitely relate to you though, even though my girl is sleeping better than yours!!
Do you have a helper? And does your hubby help out much? I know for me, I try to do most of the night stuff because hubby's gotta work the next day - but he helps me out so much in the couple of hours when he gets home and then getting her ready for bed... I don't want my helper to do the "night shift" with my daughter - but once she gets here I definitely will be trying to get her to help watch her so I can get some "me" time!!