How to breathe when there is an Elephant sitting on your chest?

My wife said I should try to learn the way she was taught in yoga classes.
Take a deep breath, hold it for a count of five, then let it out slowly.
Well, I was woken up by a violent thunderstorm at 1:30 this morning.
I could not breathe; that elephant was on my chest. I took two breaths from my emergency inhaler, and it still took an hour or more for me to accept that I was not dying. Are there any tips on how to breathe when caught in this situation? I was only diagnosed two weeks ago and told I am at stage 1 of COPD. Today was pretty normal; I was able to rebuild and repair four computers and move around the house and garage, but I have been told that this morning's episode is just the first of many. Seems like a pretty poor way to live out one's life. Especially considering that I was planning on living to the age of 101. LOL.
Keep breathing.
Regards,
Richard