There are many ways that you could go with this depending on what's happening. It does appear that your sympathetic nervous system is being overstimulated, or that your parasympathetic nervous system is being understimulated. Either one leads to a sympathetic nervous system dominance. A good start would be to find a Biocranial practitioner in your area - http://www.biocranial.com/FindPractitioner.php. They can help to bring this into balance.
Adrenal stress/fatigue and nutrient deficiencies may play a role and most liley would be interrelated. Detoxifying the body and restoring digestive balance can be an additional approach. The LifeForce Plan is one approach for this.
Keeping the bowels moving and balanced can also assist. Some of the neurotransmitters used to relax the nervous system are produced in the large intestine. Imbalance there can be another contributing factor.