Of course you are nervous, it's natural. I would be concerned if you weren't. I was a ball of nerves last week before I started a Clinical Trail I am participating in. I have been on various chemo regimens since Sept 2010, and I was nervous before the start of each. I don't remember being nervous before I started Radiation just over 2 years ago, but I think I was in a state of numb shock. I had a lumpectomy at the end of Dec 2010, and was still being treated for my advanced kidney cancer.
Take a few calming breaths, try to be kind and love yourself. Do things you enjoy, i found watching movies, in the theater, streaming or on DVD very calming. I saw lots and lots of silly comedies, laughter and a sense of humor really help.
Send prayers, hugs, and healing vibes for next Wednesday. Hugs, Calming and healing vibes for now. Keep us posted on your progress.