Being moody and difficult

I don't know how others see me but I tend to think I am (most of the time) quite amiable and easy to get along with, especially once you have got to know me well. I guess I can be wrong at times and prove to be less than friendly. A friend told me I have that killer stare ... "if looks could kill ... ", you get what I mean. Well, I do admit that I check out my face in the mirror occasionally and I agree, I have a look that can scare a lot of people, especially if I do not smile.
Well, lately, due to what, specifically, I do not know, I have been more moody and difficult than usual. I have been feeling anoyed and angry about nothing in particular, getting all worked up over the smallest things and raised my voice more often than usual. This is rather unsettling because it is so NOT the real me. And I feel terrible for the people who have been on the receiving end of my anger and what-nots.
My mum has been getting it from me a fair bit. Nothing serious really, but I have been ignoring her, and sometimes, just can't bring myself to smile at her. It feels terrible. My other half has often been on the receiving end, especially because I expect so much more from him that he is willing to give. So occasionally he gets the killer stare and that look that makes him wonder who he has married. My kids - ahhhh, yes, they too have been on the receiving end. Jon, being the eldest, gets it the most. My patience is limited and sometimes I end up screaming at him for even the tiniest of mistakes. Jeremy, my little drama king, gets it a fair bit too. Joel, well, I think I am most patient with him but .. he gets it too. When I cannot stand his lack of response anymore, I raise my voice (as if he would understand better), and threaten with the cane. Sigh! What is wrong with me? I don't like this ME. It is NOT me.
I am sorry, my family. I will try very hard to control the anger and annoyance. I will try very hard to not raise my voice or look nasty.
To the others, hmmm, well, I cannot promise I will be okay all the time. But I promise I will try my best to be more patient and to not make mountains out of mole hills.