Lacy,Getting through that anxiety period is horrible. If I can give you any advise, I'd say to hang in there and try to tolerate those terrible feelings. Do something special for yourself after a week, a month, etc...that you are there. Little rewards may help ease the anxiety.
It does get easier. It just doesn't seem so when you are in the middle of it happening. Try to keep telling yourself that YOU are in control. You can do anything you set your mind to. Remember, these people hired YOU because you were the best person for the job and they need you. Maybe being needed helps with the anxiety. I guess it's different for all of us, but stick with it. We know your pain and we are here to support you.
Kindly,
Kitt