I think if you haven't already been to them, you should go to some anti-natal classes. I didn't know what to expect during labour so I was pretty freaked out by the idea, but I have been to a few classes and now that I have some idea of whats going to happen i'm not as scared. At the classes you'll learn all about giving birth and what pain medications will be available to you.
Maybe when you get closer to your due date you won't feel as worried about the birth, i Know that now i've only got like 6 weeks or so to go I'm not that worried about the birth, i just want this baby out because its getting pretty cramped in there lol.
If you need someone to talk to you can chat to me, my email/msn is [email protected]
Another thing that might help is if you get someone to go along to the birth with you, it helps to have support.
Good Luck with everything