There are some things I want to comment on here.
Right, this is well-documented. And yes, if you don't know what it is then words cannot describe the horror of what you end up going through in some cases.
If you know what's going on, and are able to rationalize that panicking isn't going to help, you have an incredible opportunity to experiment. Depending on your mental state during paralysis you can have some incredible experiences. One of the theories is that it comes about in order to prevent us from causing ourselves physical harm by enacting our dreams.
An early experiment I did involved consciously asking to hear a "disturbing alien noise" (I loved getting a rush) and, sure enough, it came on almost immediately and would have scared the living crap out of me had I not known it was me creating it. It came on my right ear, very close and utterly surreal. I'd never heard anything like it, it was like experiencing a new colour for the first time. But, as I knew it was because of my request, I couldn't help but grin to myself. Paralysis broke almost immediately after my positive reaction to it.
I admit some fear though. During sleep paralysis I tend to keep my eyes shut as I have a tendency to fear the worst case scenario (my subconscious running away with manifestations). Well, "good stuff" happens too but I have trouble staying positive while in that state.
One time there was an entity standing next to my bed. He kept telling me about my faults and I was furious at being unable to react to him. I lashed out with a mental verbalization (which actually became audible in this instance) accusing him of not being who he said he was and that he wasn't "real". I then tried to scare him away by shouting but due to the paralysis all I could get out were pathetic wheezing noises. Then he had the nerve to kiss my forehead after which I was so angry he just vanished and I was able to sit up. Um, on my part that was an immature reaction to have had but I dislike being in a vunerable position.
Your experience is interesting to me because I've never suffered paralysis for longer than what seems like a few minutes. I started getting regular sleep paralysis around the time I was playing with exit techniques.
The projected double however (what I was talking about in regards to my first OOBE) is difficult to control sometimes. Quite often I've just had to go along for the ride so to speak. Sometimes I even find myself forced into a specific position while it floats around. It can be quite spooky.
I'll keep people updated but it's going to take time to seperate things. I have a mystery box set up in someone else's room (not done by me) and I'm eager for an opportunity to examine it (no, not physically).