Abby,
Are you sure your blood pressure is absolutely normal during one of these attacks?

Catecholamines are hormones such as adrenaline (epinephrine), norepinephrine, and dopamine. An excess of these tend to greatly increase blood pressure, heart rate, and produce other symptoms.

Although the most common symptoms are headache, palpitations, and excessive and inappropriate perspiration, sometimes people have symptoms more like some of yours : Weakness, nervousness and anxiety, tremor, pallor, nausea, exhaustion, fatigue, chest or abdominal pains, and, over time, weight loss.

Cortisol, as Crabby mentioned is the most researched of all the "stress" hormones, plus those I memtion above, but you could further do a search engine investigation of:

Corticosteroids
Corticotrophin Release Hormone (CRH)
Hydrocortisone
Adrenocorticoids
Adrenocortitropic Hormone

Are we having fun yet? :)

zuzu xx