Not saying this is what yours is, but I've also had the old hag experience.
I get sleep paralysis several times a month, have for at least 10 years.
I'm almost always able to open my eyes somewhat, and when I was younger, I'd often see an old woman standing at the foot of my bed, hunched over, incredibly aged with long gray hair hiding her face. She was never facing me, but to the side. Strangely, she never felt threatening, so I'd usually just ignore her until I could move my body again. I never noticed how she would leave. She'd simply be gone after I'd finished focusing on moving my limbs.
Now, I've had experiences of furious-feeling hateful presences while awake, but not many. I don't pretend to know what they are, but I imagine experiencing such a thing while asleep or half-awake would be much more challenging as far as not succumbing to terror.
The few times I've woken up in the middle of the night with the sense of someone/something that abjectly hated me in the room, usually in a corner opposite me, I'd similarly feel bad for it, "Wow this creature is so overcome with negativity that I can feel it across the room" and it has always summarily vanished.
If it is some kind of hateful mind, I really wish there were more we could do for them, since any kind of loving thoughts seem to drive them away.
I may be spouting nonsense, but I wonder sometimes if these are hungry ghosts. If I remember, hungry ghosts cannot stand what they most need: water seems like piss, food like vomit, and they crave the very things that turn to fire in their bellies and prolong their torment. It wouldn't surprise me, if this is somehow connected, that hungry ghosts flee the healing love they need and seek more hate and fear instead. How very, very sad.
I've often felt deep sympathy for villains in stories, or even the demons in the Bible that Jesus drives out, so I wonder, Jesse, if your encounter with such things isn't your own compassionate wisdom perceiving and offering solace to such things, even if they are only aspects of your mind or emotions.
Hope that wasn't way out of left field. Just some thoughts.
If you find one thing wearisome, you will find everything wearisome. - Dogen