reverse blinking/sleep paralysis

so I recently tried the reverse blinking technique while taking a nap in the afternoon. I was at the point where I could feel that my body was asleep and I started to feel this downward pressure on my body as if I was sinking into my bed. Also I felt like it was a little hard to breathe. But then after a while it just went away, I just couldn't fall asleep. Is there something I'm doing wrong?

Concentrate on the swirls on your eyelids when your eyes are closed, and also concentrate on your breathing. For me, if I go cross eyed, it either puts me into the dream, or SP.
Sleep paralysis only happened once for me, and it was FUCKING SCARY SHIT, as something was knocking on the cupboard behind me in pitch black, moaning and I couldn't move even though I was lucid.