Sleep Paralysis

Firstly

first most important thing is how to deal with it in the moment:

1. DO NOT TRY TO SNAP OUT OF IT, you will just stress yourself and panic yourself

2. recognise that it is happening -- this takes practice, but you can

3. train yourself to breathe super slowly. The feeling of being unable to breathe is, IMO, because we are lucid, we are feeling our body, but our sense of time is different, so it feels like we can't breathe. Actually we can breathe, so if you allow yourself to breathe really really slowly, you'll realise that you are fine.

In my experience, the panic of being unable to breathe is half, maybe even 90%, of the battle, because that induces additional fear, and wondering why we can't breathe, what's causing it etc, thereby also inducing apparitions to explain why we can't breathe — e.g. demons, nazguls, ghosts, beasts on your chest; a gunman standing by your door, etc.

Secondly

Second thing:

Identify any patterns related to sleep paralysis.

For example, I noticed that I typically get sleep paralysis when laying in specific positions. So I avoid sleeping in those positions. I made this so important in my mind that I even recognise those positions when I'm slipping in and out of sleep, and manage to reset my position back to a safer position.

Thirdly

Third thing:

Sleep paralysis usually occurs during periods of time in my life, I get it often in one period, and then never for ages and ages.

This leads me to believe that it is related to things in my life and environment. May be from some stress (maybe unconscious stress so do some reflecting on your daily life), may be from poor blood oxygenation, may be from lack of certain nutrients, etc. Take your body's behaviours as symptoms and do a full health maintenance.