I'm the same way right now. I'm 15 weeks pregnant with my second. I've been able to feel him/her move every now and then since about 12 weeks. I've had two ultrasounds and heard the heartbeat once. I had pretty bad morning sickness, but it seems to be fading this week. Yet it still hasn't totally sunk in that I'm pregnant right now! I'm already showing, and I'm mostly wearing maternity clothes. The rest of my body is slimming right now while my belly grows (I've lost about 10 lbs :( ).
I think it has to do with caring for the older child, and usually your life is more busy (at least mine is) so it doesn't sink in until later for some women.
It really feels surreal to me right now. I have my ultrasound on May 7th, so I'm hoping that maybe once I find out the gender (hopefully), it'll sink in that I'm actually pregnant!
It's not fun, so hopefully we can both get through this soon!