I just recently found out I was pregnant at 4 weeks and like others I had always said that I didn't want kids so the shock of seeing that positive pregnancy test put me into a depression for at least 3 days. I cried everyday, didn't eat and was a zombie at work. It literally felt like a prison sentence. When I told my husband, he was so excited and happy and I was nothing but resentful. I got it in my head that my career was over and my 10 years of education were for nought.
I think with most traumatic experiences you have to mentally and emotionally let yourself work it out. Denial, anger, bargaining, depression and acceptance are all a natural part of the grieving process (and yes, we are grieving for the life we once had) and each of those steps takes time to work through. As for myself, after all the tears, grief, resent and thoughts of how my life as I knew it was over, I made the conscious decision to keep doing the things I love to do (sans sushi and alcohol which in itself is depressing!) and not become the stay at home mom that sits on the couch all day.
Although I am still working through the grieving process in my own way, it is getting easier. By making the decision to stay healthy and active, not give up on my career and understanding that having children is not the end of the world (working women do it everyday, right?) I have actually been able to see the light of life through the tunnel of sadness I created for myself. Just remember you're in charge of your emotions, and this too shall pass. As quoted by Emily Dickinson, "If your nerve deny you, go above your nerve."