Amy ,there are also other things to take into consideration of why Poppy is acting like this.
Right now, I don't beleive it is fear or anything like that - well, not in a round-about way.
She thinks you need protection maybe. She might think you are not the one who can take care of everything. You know you are, but dogs osmetimes think otherwise, due to their upbringng and events/socialisation etc.
Sleeping ON you, or UNDER you is not a good thing to allow her to do, especially in light of her recent behaviour towards strangers. She has to learn that you will rule this house, you will make decisions of who comes and goes, YOU - NOT HER.
Hope that mkes some sense for you. Too tired to get into it and explain at length - I;m sorry.