Aww, I completely understand how you feel! I was terrified when I had Chelsea spayed last year. I kept watching the clock, and called the vet's office so many times they had to be getting annoyed. I'm sure your baby will be fine, and I don't think it will change her personality any. As far as her smooth little tummy, you're not being silly at all!! I actually had the same thought once I brought Chelsea home and felt her incision. It may take several months, but the scar will eventually fade almost completely and she'll have her smooth tummy back again!
I would ask your vet about the walks and about making her comfortable. Chelsea had a great surgeon and was feeling great within a few days.
You and Addie will be in my thoughts and prayers tomorrow!! Please let us know when she gets out of surgery.
__________________
He is your friend, your partner, your defender, your dog. You are his life, his love, his leader. He will be yours, faithful and true, to the last beat of his heart. You owe it to him to be worthy of such devotion. -- Author Unknown