Learning that you're not alone helps to break that cycle (even just for a moment) and brings things into better perspective. One of the key things I had to develop years ago was the skill to restore perspective to my thoughts (that task-breakdown thing is just one thing). When I find myself becoming angry, I have to ask myself, "Is this an appropriate response?" Some drunk just took off the front half of your car? Anger may not be helpful, but it's appropriate. There's no more milk in the fridge? The anger is not warranted, take a breath, realize that you're stressed, and put "milk" on the grocery list.
And substitute all negative emotions into the above. At my worst, I'd get emotionally sad over incredibly tiny things like spilling a bit of salt (not even the whole shaker). Examine that emotion when it rises, don't try to stop it but examine it. Ask if it's appropriate, ask if there's another cause or other factors involved.
It's not necessarily easy, it depends on how stressed you are at the moment. But if you try to make that a habit of thought, over time it becomes easier and almost automatic.
Additionally, please consider seeking out a therapist. Having someone to speak to confidentially and who can help develop these kinds of skills is incredibly helpful.
