Hello,

Well I am not sure what happened to you was nothing more than a anxiety attack, but I to was awaken with a racing heart, buzzing in my left arm, it felt like someone was squeezing my wrist and the circulation was being cut off on my whole left arm, I had shortness of breath and was sweating and it scared the heck out of me and I was sound asleep.
I had a Panic attack so the E.R doc told me and that they don't know why it happens it just does.
I to have being going thru alot of stress for a few years and eventually if you don't deal with it, it causes your body to react in away of making it feel like I was having a heart attack.
But get checked by your Dr. just to make sure it's not your heart or anything else....good luck and peace dabella : )