The symptoms sound like a "Night Terror". They are more common in children. But, a few years ago, I was in the hospital. They lowered my blood pressure too much and I had the exact same symptoms. It was horrible. I was hooked up to an EKG and I called the nurse and asked her to check it. The next day the doctor came in and apparently she had been called when it happened. They told me there were no abnormalities but I think they were trying to cover their liability for giving me too much medication. I was even afraid to go to sleep when I got home.It gradualy went away. I know certain medications can do that.
I have had a vasovagal reaction from a chiropractic adjustment that was done wrong (I love chiropractic, this was just a rough bad doctor). The symptoms of that were very nervous, dizzy, felt like I had to have a BM. It was completely different for me compared to the above experience. So I don't know what causes it, but you certainly have my sympathy cause they are no fun!
I don't know if adrenal fatigue could cause it. It sure could make it worse I would think. If you are getting erratic releases of epinephrine and norepinephrine it would make you nervous. Some sleep disorders can cause the seizure like activity when you are faling asleep. You are supposed to be paralyzed when you are asleep, if that is malfunctioning, which is does to most people every now and then, you will be aware of moving and it may be attached to a dream, or a feeling of falling.
I hope you get it figured out, or better yet, it just goes away!