DD is 5m, and I went back to work last week (that's all the maternity leave I get, no option to take unpaid or anything). Up till recently DD slept fairly well, a couple of wakes per night but quickly back to sleep on the breast. Since last week she's waking every hour or more. Sometimes she just needs a cuddle, sometimes a feed. I haven't been so exhausted since her first week at home!
We couldn't get her to take a bottle before I went back, so that's been a sudden change. She's barely eating during the day. It's also coincided with moving to a proper cot as she can sit up and the Next2Me was no longer safe. She's still next to my bed though.
DH is on paternity leave, but he says there's no point him seeing to her in the night because she won't settle for him. To be fair, as she's in our room, it's true I'm going to wake up anyway (although he mysteriously doesn't). So I'm up every hour or more, then I get up and do a 10 hour day including 20km up and down the motorway. This morning I left DD in our bed and came to the sofa, and woke an hour later when DH snuck up and started bouncing her on my chest 
How on earth do people do this?
Sorry for the long post. I'm feeling sorry for myself.