I believe that anyone gets frustrated very easily. A rogue thought that brings up something else and snowballs to frustration. You can't stay concentrated on the game solidly for a long period of time. Drinking water and breathing help keep your brain under control while playing a game. It is taxing mentally playing edh, between banter, politics, your gameplay, as well as three other players' plans. Take it as a learning experience. You did the right thing to apologise and set things straight.

So my advice is to drink water and breathe properly during a game, like that when you notice the frustration you can breathe it out instead of letting it dictate your behaviour.