On freaking out…

My question concerns a thought I had recently about anger and angry reactions possibly being buffers and/or protective responses of the primitive brain.
I have been raising my three kids alone since my divorce over 4 years ago. I am usually very patient but go non stop all day and evening and when I feel overwhelmed I tend to say and do things that I later regret, such as yelling, slamming doors, and listing everything I do for them. This only results in my kids feeling scared and upset and me feeling guilty for getting angry and like a big failure. No time is added to the day by my angry venting; no greater number of chores have been completed: no communication has occurred. Yet even when I say to myself that I will never do it again and find a better way, it happens again almost automatically! It’s as if I have the impression that these explosions will give me relief from overwhelm but in the end I feel worse than before, like that bloated queasiness after eating fast food.

Here is my model (unintentional)
C = overwhelm
T = I can’t take this anymore, I am not a slave
F = anger
A = yelling and slamming doors
R = kids are scared, I feel guilty, no love

Can you please help me understand why my anger is so automatic and perhaps come up with a believable intentional model? Tried to create one but got nowhere because I get angry so fast in these situations. xo