they feel like you are literally about to die. The first time I had one, it came out of nowhere. I was sitting at my desk at work when I felt a little dizzy. I decided to go on break and go downstairs. Well as soon as I got to the stairs, my head started spinning and I had this enormous feeling of being scared shitless. I honestly thought I heard a voice in my head saying you're gonna die. I had to sit down b/c I thought I was gonna faint. I then went downstairs to smoke a cigarette and luckily there were a couple people down there that I could talk to so I would calm down. After it went away, I had mini attacks the rest of the day. It is truly a horrible experience