Pounding Heartbeat at Night

For the past few months I've been having slight issues sleeping due to a pounding heartbeat at night. It's gotten better since I started taking calcium and magnesium at night, but it's still bad enough to where I can't sleep on my stomach like I normally do. It started shortly after I saw an naturopathic MD regarding my moderate-severe adrenal fatigue. She gave me some herbs to take, which I did, but after a week of taking them my heart would pound so hard at night that I got no sleep at all. I reduced the dosage of the herbs and that helped for about a week, then the pounding came back. Stopped taking them altogether and it still didn't go away. During this time I also eliminated gluten and found out that I have a mild-moderate gluten intolerance (can't eat pasta at all, bread is ok in small-medium quantities) as well as being lactose intolerant.

I contacted Dr. Lam regarding this issue and he said that it had to do with my body being flooded with RSR which is a neurotransmitter associated with "fight or flight". Of course he didn't tell me how to fix it other than that it was in his book. I didn't want to buy his book JUST for that information, would anyone be able to tell me what's going on and how I can fix it?