Hope you get to feeling better, MM.
What sort of space do you think of as a safe place? I don't know if it would be at all what you are thinking of, but I've had a place that was as simple as a couple of big pillows in the closet on the floor under the clothes rack. Called it Hide-y Hole. I don't know if it was a safe place as such, but a place to retreat to when overwhelmed, or when I really needed the floor (hard to explain….a depression thing). No alteration required.

(Currently don't have one. I'd do the same here, but it's a really small place, and space is at a premium. To say the least. I may have to burrow one out sometime though…Which is how the first one came about. Had to get in THAT space. It was the only one that felt sheltered enough. It was a comforting place.)