I too, work 12-hr shifts and I hate leaving my dog at night but I have made it work best I can. I have baby gates on both entrances to my kitchen so he has ample room to roam around. He DOES get bored. I learned this because my wooden kitchen chairs are chewed down to almost nothing at this point! He doesn't do this when I am home. He does use the restroom in the kitchen but it's easy to clean up and it isn't often. The other difficulty is when I do get home in the mornings, I am ready to sleep!! I stay up with him for about an hour or so. I set my alarm and wake up twice on those days that I do sleep to feed him and let him out. He stays with me in my room and pretty much sleeps with me. Luckily, he doesn't go to the bathroom inside the house or my room. He is my shadow. I love him so much. He is so lovable and sweet that just like a human child, I cannot imagine life without him.
Right now where I live it is so terribly hot that we simply cannot go out for walks. I hate that part of everyday because I am huge on walking him daily. I am a big believer that walks are essential to having well rounded dogs. We don't walk far but they need to get out and burn some of that energy!!
Good luck to you!!