I have a temper. When I feel out of control it is scary for me.
As a result, I sought to develop coping strategies as early as I could. My DCs know that if I say I need to step away, I need to step away. I usually go for a walk (just around the house if there is no one to keep an eye on the youngest), or go chop wood for the fire. I also put myself in time out.
I have taught the children since they were old enough to understand language that losing your temper with someone is not acceptable, and other ways of managing anger need to be found. DD goes to her room and plays out her feelings, DS goes for a bike ride, listens to music or draws, DH goes out and works in the garage.
It is normal to get frustrated with your family. My DD is 11 but has the cognitive age of about 4 (she is cognitively and physically disabled). I can assure you that she can be very frustrating from time to time (and here, we have 10 weeks for summer hols - talk about wearing on patience) but that NEVER makes physical violence and threatening behaviour acceptable.
What the OP did was unacceptable, end of. It was violent and abusive, and trying to minimise it by blaming it on a monthly cycle or saying the children "looked sheepish" further cements her lack of control and remorse. The only reason the children would have looked sheepish and not terrified would be if this is a regular occurrence and they have become desensitised.
It would be prudent for the OP to find support immediately, before SS does it on her behalf.