I attempted the "counting" technique last night, where you simply count in your head and attempt an RC after a while to see if you were in a dream. Well, after I began counting and repeating "I am lucid dreaming", my heart rate got to ridiculous levels. I could hardly hear my own thoughts over my heart pounding, and I think this may have kept me from going back to sleep. Any thoughts on why this happened? I think it might have been overexcitement or my inherent fear of sleep paralysis kicking in, but I was getting a very odd tingling sensation and might have actually been losing consciousness.

What do I do?