Ya, I agree, I wouldn't leave a dog that small outside alone all day for the above mentioned reasons. An idea if you want her to have more room to play and move around while your gone is you can get an indoor pen (it's like a couple baby gates attached together) or confine her to a room like the kitchen with a babygate (as long as she can't possible get to anything dangerous that is). That way she can have access to water, safe toys (like a Kong or something else that's basically indestructable), and maybe food and a piddle pad
As long as you're providing an area that is comfortable and has any necessary items that she'll need for an extended period of time, she'll do well while you're at work and get used to it. And congrats to you for rescuing her
