Sleep paralysis experiences vary hugely from person to person. It is much more intense for some people than others. I will have to disagree with the whole "dream within a dream" thing and say that falling asleep in a dream is really just changing the scene although I cant back that up with anything more than personal experiences. Definitely try to reality check whenever you wake up to prevent being fooled by false awakenings, and the next time you are in SP I recommend you don't try to fight it at all, relax, and remain aware until a stable dream forms.