bumper....wish I could add somehting, but Derlor and Foxy have summed it up really. ((((((((hugs))))))))) to you. It is scary, and it is overwhelming, and yes....that bay has got to come out and I think what you are feeling is just a natural stage of pregnancy and part of your mind/body preparing itself for the changes to come. You'll get through it and you'll be a better person for having gone through it.
I've been full of doubts as well the last few days, like "OMG what the fuck have we done!!!!" I think it might be a final hormonal rush or something, and have been having a go at DH as it seems to be all down to me to sort things out. I think men just deal with it differently, it doesn't mke them a worse parent.
Your own kids, like the other two have said, are fucking brilliant, and you will love this one more than you thought you could ever love anything in yor entire life (even more than chocolate and red wine )
Keep talking to your DH though....and more ((((((((((hugs)))))))))))) from me