Hi Michael,
What you are feeling and the symptoms that you are receiving are all very normal indeed. I too have experienced exactly what you describe, and even sometimes now it comes and goes but once you learn to manage it, it becomes less and less.
It sounds to me that you are experiencing some anxiety and a wee bit of panic also. Are you under a lot of stress in your life at present? as this could be the underlying cause of some or most of this.
Have you tried, meditation as this is very relaxing and completely releases you from any fear and relaxes your tense muscles as well, which will in turn calm down your mind if it is any way overactive. Also, speaking of herbs, have you tried to drink some chamomile tea, which is completely caffeine free, this also helps a lot. Also rescue remedy is another.
Take care hun,
Sunset555
I should probably also mention that once in a while my anxiety will lead to nausea.