Oh I hear ya, I felt like this when I finished up work a few weeks ago. It was particulary hard for me because I am a teacher, and not only was I leaving my job but I was leaving my kids as well. Thething that made it hard for me was that I had worked sohard in the first term to get the kids under control etc and finally they had started to settled down and get into a great routine- then I had to hand them over from someone else.
I have been back a couple of times to visit but it made me feel sad because I felt disconnected from them, and I felt that they weren't 'my class' anymore. The other thing I found hard was having nothing to do, the day to day work I didnt miss so much because I found it tiring, but all the planning and preparation I did in my spare time, stuff that I really enjoyed doing- I didnt need to do anymore.
I am sure that once the baby has arrived I will feel much better, but it is that whole waiting game...........