I'm sorry you are so tired and stressed. I know when I get exhausted I get completely overwhelmed and I can't handle one more minute of it. But then when things calm down again, I feel like I can again take on the world.
I can give you some suggestions on how to make it easier, but eh, I don't think that's what you need right now.
So I'm going to tell you to hold on tight. let the things go that can. Your house can be a mess as long as your kids are fed and clean. The family could eat some crap food until thing calm down a bit.
Fine, I will make one suggestion, and it's helped me. My D would like me to be at everyone of her football/cheerleading games, even on her dad's time. I take atleast 2 in the season where I say I'm sorry, but I can't make it. She gets over it pretty fast. Maybe if your ex will be at the tournament you can step out for a bit, do something nice for yourself and let him root them on.
Zues, villages used to raise kids. When I was talking to my IC, she said to look up some local single parent groups where everyone kid of takes turns doing things. Someone will cook dinner for everyone at night, someone will take care of all the kids while one gets stuff done. I've been thinking about starting something like that locally.
I hired a cleaning service for once a month yesterday. Something had to give for me too. And after work, school, kids, activities, I just don't have it in me to scrub toilets. So I hired someone to do it. If you could budget in a little bit of help, it might be worth it.