This was how mine basically started too. Though mine were mainly after not sleeping all night, night after night. I have CFS also, and with the insomnia..the exhaustion was so much, i could not fight them off.
I couldn't really control them for many years, and they were one of my worst symptoms..feeling like i was going to die..over and over again.
As mine were from exhaustion..and i do still get them from time to time(even though my exhaustion levels are the same), idon't know if i could help you much.
I guess i tried just to accept them when they happened..to not highten the fear, and to listen to my body(for me not doing to much when tired especially).
For me the best thing was to get as cold as possible..no clothes etc(if at home of course). I found this helped slow my breathing etc sometimes.
This by no means helped all the time though. Medications did not help my panic attacks, but i hope the above helps a tiny bit at least.
Take care