That's disappointing - I know it's one thing if you get pregnant KNOWING they will be gone, but for it to come up unexpectedly- it will take some time to adjust.
PP gave good advice - make sure you build up a support network if you don't have one already.
DH deployed right after DS was born and missed about 8 months. It's hard when they miss all of those "firsts," but I tried to keep him as up-to-date as possible on all of the new things DS was doing.
I am sorry, that does suck! We found out when I was about 14 weeks along that my H would be deploying shortly after the baby was born. It is hard to hear at any time, but all the extra hormones sure don't help, I was a hot mess for a while.
He left when she was 7 weeks old, she will be about 11 months when he gets home. I send him pictures all the time, we skype, I send him videos of all her firsts. It is not as good as him being here, but the technology we have today sure does make it easier.
Do you have a good support system? Family that can be there when you deliver and to help you out, especially in the beginning?