I have had this happen so many times. When I think about it I could have probably had more than a couple hundred lucid dreams by now. The funny thing is I noticed that the more I'm covered up by my sheets the easier it is for me to notice the paralysis. I had to convince myself before going laying down and while laying down that there was no way for me to suffocate and that if anything the sheets would fall away from my face and allow me to breathe better. I was sucessful once and had a lucid dream with full control. The hardest part about this is staying down through the fear. You have to convince yourself that it is an illusion about the breathing being harder. It is just that normally you don't feel the paralysis happening.