I have been having rapid heart beat for the past three days! I am cold then hot and repeat! I am shaking periodically and and trembling. I am nervous all the time. I am exhausted all the time. I can't do my job at work due to running out of the office and hiding in the bathroom taking deep breaths. I am so afraid I'm dying on cancer of something terminal. I often run outside to catch my breath or go for a walk around the building to calm down. I have dizzy spells through the day. I sweat at night and wake up from nightmares I can't remember! I feel like I'm going crazy and I'm losing my mind. Am I alone? Is this anxiety?