I got Cooper about 3 weeks ago. I am a teacher and because it was Winter Break, I was able to stay home with him for the first two weeks. Monday was the first day that I left him, for about 7 hours. I bought a baby gate and block off my laundry room. There is absolutely nothing he can get into in this room (believe me, I have a very NAUGHTY Jack Russell and even he can't find any trouble to get in to). I have his crate, food, water and some toys. When I get home he completely loses his mind, but seems to be adjusting well to this change.
I am sure your little girl will be fine. Like an earlier poster said, I think it is harder on us than them! Oh, the guilt!