Is it normal to be terrified of giving birth?

My baby is due in 14 days and when I think of the big day it absolutely terrifies me. Is this normal? I am excited too because I want to see the baby I have been growing so long but the actual birth has me freaking out.. did anyone else have this problem? If so what can I do to not be so afraid. I suffer from anxiety disorder and I am scared that if I can't stay calm when its time for little Zo� to get here that I might have a panic attack.