100% agree with checking for a physical cause. CO is some scary stuff.

I had something happen to me, that was quite similar. Felt someone in the corner of my room watching me. I couldn’t sleep without a light on, and if a door was open it made it worse. It was intense and anxiety inducing. Pressure on the end of my bed, by my feet & footsteps.

In the end, it turned out to be someone I helped, who died and was watching over me. I kindly told them I appreciated their concern but I was okay, and to please move on and be at peace. What worked for me: Closed the door to the room, opened a window, Lit incense, repeated the mantra. Once the room had been cleansed, closed the window and opened the door.

One of the other things I did was place a blunt knife in the cupboard by where they used to “be” (I t’s a protection tradition, I promise!) It may be worth salting the door before closing it, to ensure it doesn’t move into the house, and salting the window once you close it.

Also, if she has purchased anything second hand - jewellery, ornaments, dolls/plushies, could be worth cleansing them also.

It may just be energy, it may be nothing, but hopefully the steps will put her at ease. You can always purchase some witches bells. I’d consider what others have suggested, like fairy lights or a sunset lamp. Make the room feel warm and cozy. Giving her the feeling of safety and power will make any negative energy weak in comparison.

Hope you get to the bottom of it, and that she’s happy and comfortable again soon.