It sounds a lot like sleep paralysis. The fact that you could move your head a little bit makes me not 100% sure on it, but the rest of the description matches SP a fair amount. Did you feel any heaviness in your chest or did it seem like it was hard to breath/someone sitting on your chest? This is a common symptom of SP and if you did experience it, then I'd say that it was SP. If you didn't, then it may have been either SP or just a weird dream/FA.