What do you do when your nerves are shot?

Soon upon waking up today my nerves have been shot, every single innocent and non detrimental thing my 4yr old kid is doing right now is driving me crazy, I just want him to sit down and stop moving/squealing. I know this is natural and I need to chill out but it's just one of those days. What do you do when you feel on edge and easily irritable over nothing? I tried relaxing for a moment and recognizing that all that I'm irritated with is natural and healthy behavior but it's not helping me. Could this be an issue of nutrition?

Any advice would be great, thanks.