Guy, the perception that some entity is sitting on you/clambering up on you from the end of your bed during sleep paralysis, is known as being hag ridden.
I'm horribly familiar with sleep paralysis. I'm amazed your wife could detect your signal/noise, Sagat. I'd be screaming til my lungs felt like they'd burst and not a sound would escape my lips. Sleep paralysis is like being embalmed and mummified but conscious all along. With a malevolent dark shape coming for you.
My SP started soon after I'd undergone a spinal epidural injection and I have to wonder. The main risk with epidural is paralysis.