Definitely the sleep deprivation. But even being told about how bad it was going to be didn't really prepare me for when it actually happened. I can understand why some people used to use it as a form of torture.

At my antenatal class the midwife said "Giving birth is like doing the biggest poo of your life!" I had no idea how true that statement would be LOL I kept telling the midwives that I needed to poo (sorry TMI) and they just said, "no dear, I think you're just having an urge to push"

Also that you still have a belly after you've given birth. I don't know what I expected to happen to it, but I wasn't expecting to still look pregnant.

And, I don't know about anyone else, but for about 2 weeks after I'd given birth, if I wasn't near DS, I always thought I could hear him crying. I felt like I was going mad.