It sounds as though things are understandably very difficult for you right now having such bad memories triggered. Do you know any grounding techniques? These can sometimes help bring us back to the present. There is an article
here describing some of these techniques.
I'm sorry you mistook a family friend for his wife, have you explained to her why you reacted the way you did? Hopefully if she understands why she will be more inclined to by sympathetic than upset/angry.
With the breathless feeling I personally find breathing in counting slowly to 3, holding the breath for a second, then exhaling slowly counting to 3 helpful.