I hear you! There are definitely days like that. I don't have a solution, but I can tell you that you're not alone! There are days when I don't even like the person that I become...and my kids are still in my daycare with me. So, I'm doing this because I don't want to send my kids to someone else, but then I don't even like who I become.
I find that the harder I am on myself the worse it gets. There will always be tidying to do, dishes piling up....sometimes, you just have to leave it there. I've lowered my standards and I find that helps!
I also am trying to put less pressure on myself. I know that I do way more and give way more than what these kids are getting at home. sometimes that's great, but if it means I'm going to burn myself out, I'm not doing anyone any favours. Kids are great at just playing. The more you leave them to their own devices, the more used to it they get. Not, that I neglect them, but they have learned to play much better on their own!
Hope it gets better!