Sorry, I can't help. I think you will always get to breaking point sooner or later. You just need something to help you release the tension.

When I reach breaking point, I go into another room (as long as the boys are safe of course!), grab a pillow and beat the crap out of a bed. It releases tension and makes me feel a heap better too. The kids have followed me a couple of times. I turned around unexpectly once and both had their mouth open. I thought they were going to cry because mummy was a bit scary but instead they laughed themselves silly. Made me laugh as well and really brightened up my day.

Good luck and I hope your day gets better.