Hi Madvorak!
Whenever you find yourself in SP - whether in your real body or in a dream body - the absolute worse thing to do is try to move. What you have to do is just leave the paralyzed body and float in another dream body as Dolphin suggested. Don't make it complicated. Just relax and imagine floating out or rolling out - it will happen very easily.
Then, after you are out and mobile, it's very important to stabilize the dream!
If you don't do it, then it will fade away as you say it does.
Don't rush! Relax where you are and feel all sensations - feel the world around you!
Touch you body, rub your hands, look closely to whatever is around you, smell the air etch. You can also try saying : Clarity Now!
Sometimes it works great.
Then, when the dream is stable, go for your goals!
Good luck!