It seems like your frustrated. In my anger management counseling sessions I learned that frustration is an rung on the ladder of anger. When you yell at the kids it is anger. After anger comes rage. Let's get you managing the emotion better before it gets to that.
I learned the best tool for anger management is mindfulness. Take a step away from the anger look at it from inside you head. Observe it, acknowledge it then let go of it. I was taught if you don't act on the building anger and start to actively observe it for 90 seconds the anger will dissipate. In the beginning I may take longer but that's the idea. I now see my frustration building and observe that. I nip the anger in the bud before it even develops.
If you want to join Karate again or take boxing do so but that will not be as effective a tool as anger management. Meditation helped me a lot with my manage anger. Just saying.
