Rumbling

In one of my confusing cycles of false awakenings, there was one that stood out from the rest. I opened my eyes to see my room. I was lying on my back. Usually I sleep on my side with my legs drawn up near my stomach, almost in fetal position, while hugging a pillow under my head. But that is not what made me suspect it was a dream. My vision was blurry, I felt vibrations in the back of my head, I heard the sound of what could be my facial muscles tensing (try making a huge grin all the way to your ears, you will hear a kind of rumbling / underwater sound). I recognized all these three signs from past experiences with sleep paralysis (or dreams of sleep paralysis) and thought knew what was coming; a bit of noise, vibrating vision and colorful hallucinations. But what I got, was the terrifying experience many people talk about. I could not move, and I felt a presence by the side of my bed. I was scared and wanted it to end, but I could not do much before I knew if it was a dream, and I had to perform a reality check for that. My reality check of choice is to clench my nose and try to breathe. Problem is, how do you do that if you cannot move your hands? I fought hard to lift my hand - it felt like there were concrete blocks attached to my arm, weighing it down - and eventually I got it up to my nose. I clenched it and I could breathe! Now the dream would end for sure, like all the other times I discovered I was dreaming in the past months. But it did not. I tried to open my real eyes (or my eyes into the next dream, I am not sure), but they too were weighed down by concrete blocks. I woke up in my bed again, terrified. Thought maybe I should do a reality check to make sure I was awake this time, but it felt so real I did not bother, and slipped away, either back into sleep or into the next dream. Right now, I am not sure if I was even awake.