I don't meditate in a sort of Zen way very often. But I always try to keep in mind what my mom uses to say: "If you are within youself you can't be beside yourself with sth. (translation?! German version: " Wer in sich ist, kann nicht ausser sich sein.")" That helped me already in many stressful situations when I just stopped, thought about this sentence and went on more relaxed, centered and focused.