It sounds like you are really struggling. I wish it weren't all coming at you at once, but that is the way it often happens in life. Just keep telling yourself, "This too will pass." It helps to realize that you HAVE made it through all the other stressful times in your life, and then there was Paris. Every time. You well know what grief looks like and that all the stages just have to be gone through. Not comfortable, not fun, but necessary. When you are off, give yourself extra rest and care. Do something special for yourself. You deserve it.

As far as being a dumb s#$t, you are far from it. You have a loving heart, and you saw a dog in need, so you gave him a loving home. You are to be commended. You are just not in a good place to deal with a new dog's transition right now, so it is making it harder on you than it normally would be. New is always hard. Exhaustion and grief put it on a different level of hard. It is not your fault nor his.

I understand your feelings about a shock collar. I felt the same way until I was educated. A mild shock does not hurt the dog; it startles it. Think about when we first got pagers or phones that vibrated when we had the sound off. We would jump out of our skins. It didn't hurt us, it just startled us. Same with a shock collar. Believe me, I get shocked frequently from my defib, and I don't even notice it now. It was always the startle factor. A sharp no and a gentle jolt should teach him not to bark at the cats, then you can teach him that you love them as well as him by letting him see you pet them, then him. It can work.

Funny story: My cat and dog have always loved each other from the first, but my mom's dog caused my cat to climb the screens up to the overhead beams of the Four Seasons room with his insane barking and charging on the first day he was at my house. It took all of three seconds and was over by the time I figured out what happened. Even when he saw a cat or squirrel out the window, he would bark and carry on like something crazy. A neighbor's cat had kittens in Mama's shed. The dog couldn't get to them, but he went crazy when he saw them. When he went outside, the rest scattered quickly until he went back in, but one of them started coming just outside his run and would stand and stare while he barked. It seemed to get satisfaction out of driving him crazy. It kept doing that until he just stopped barking and stared at it. He would run outside barking and scattering the other cats but when they were gone he would smell the tiny ball of white just outside his reach. One day it came through near him and rubbed on him. He crumpled. Needless to say, that cat stayed when they came to get the rest to re-home after they were weaned. Now they are the best of friends and play and lie together. It CAN happen.