Russ,

I've been there and can help. Here's what can help calm your mind.

Magnesium Glycinate (KAL makes one I use)
Taurine is an NMDA antagonist and can help
Theanine potentiates GABA and Dopamine
Lithium Orotate or Aspartate
Valerian potentiates GABA
Zinc is an NMDA antagonist and can help
Lysine is an inverse NMDA agonist and can help
Melatonin for sleep. High enough dose to keep you out.
And GABA

B3 - niacinamide seems to have a synerigistic effect with GABA.

Rx Klonopin helped me but had the side effect of added depression.

You should look into the new derivatives of GABA like Phenibut and Picamilon. If you take Piracetam with Phenibut is supposed to keep you from developing tolerance. I haven't tried Picamolin yet but it's GABA bound to niacin to help it cross the Blood Brain Barrier. I'm very interested to try Picamolin.

I'm not convinced of what causes this. For me it occurred during my period of extreme stress and its definitely chemical. I also usually had heart racing as well which made me thing it might be Adrenaline and or NE. I also think it could be cortisol (early stage adrenal fatigue) or possibly lyme neurotoxin. Or all of the above in a domino type effect. You are definitely getting chemical stimulation of some type.

Cheers