My opinion matters little, really, but reading all these posts is kinda like reading my own health journal. I was convinced for a long time I was going to die any day. I just finished writing a post about the period of my life I spent sleeping because I was depressed. It was shortly after I shook myself out of that behavior that I discovered I had anxiety. I started paying attention to all the little aches and pains and oddities of my body and convincing myself they were something larger, but then trying to push those feelings away for fear giving serious thought to them might make them real.
That's when I started having the sleep thing, where I'd wake up right as I was falling asleep, fearful that I might die. It got so bad one night, I fell out of bed and thought I was having a heart attack. That thought pushed me further into my anxiety attack and I collapsed on the floor as I was trying to get up. All I could think of was trying to get someone to help me, so I crawled up the stairs trying to find someone else in the house but no one was there. I would have called 911, but then in the back of my mind, something told me I wasn't going to die and I was having a panic attack, and I should just relax and drink some water.
That voice was actually my wallet, as it was empty and needed to do something to occupy its time. As soon as I started thinking about what it would cost to go to the Emergency Room, especially if I called 911, I suddenly realized I might have been wrong about dying, and by the time I finished drinking a glass of water, I also realized it had taken me over a half hour to crawl out of the basement and if it was a massive heart attack, I'd have been dead already.
The next day, I went to the doctor and he confirmed I had no signs of having had a heart attack. That was the worst attack I've ever had, and it came from reading way too much WebMD and being extremely depressed and having nothing else to do with myself. I've had some episodes since then, but I realize what they are and I'm able to calm myself down. The last time I had an episode of waking up like that came right after I got laid off from my last job, but I'm alright now.