I would go see a Doc and get some blood work done.
The adrenal has many different functions, from regulating blood volume, salts, body water; energy production; inflammation; and of course, the adrenal medulla that produces adrenalins (epi and NE).
However, the adrenal is signaled by the pituitary and the sympathetic nervous system. So, your pituitary may not be functioning correctly.
Then again, thyroid hormone also plays a role in arousal and energy production, so perhaps its an issue with the thyroid.
And, complicate matters further - stimulants interact with neurons in the brain and effect brain chemistry.
Caffiene antagonizes adenosine receptors in the brain to increase arousal. However, extended caff use results in an upregulation of adeno receptors (hence tolerance to caffiene). Ephedrine and other eph alkaloids also effect NE in the brain, as well as EPI release from the adrenals.
Stop the stimulants. Get some blood work done. Get healthy.
What is your resting HR and BP like? How do they react to exercise? Lets not forget prolonged usage of some stimulants increase risk of cardiovascular incidents.
Br