Thank you all for your comments. It's really nice to know that you're all on my side. I am definitely way out of my element.
Anyway, here is the deal. She is willing to give me the spare key. The elevator key is electronic so she definitely cannot copy that one and the apartment key says "duplication prohibited." I told her I'd pay her on a weekly basis, and as long as things are ok each week, that I'd keep staying.
I also told her that she cannot come in to the unit while I am here, while Dexter is here, or while my things are here. I was very nice about it and explained it wasn't personal but that if all of this followed her I couldn't handle it. I need to know that we are both safe and that nothing else will go missing. She says that these "spirits" mess with her so I figure if she doesn't come over I'll be ok?! Ugh.
What do you think? Should I just stay here?
I found a place for $300 more without a washer/dryer in the unit and also found a hotel where I could afford to do 2 weeks, but that sounds like a horrible option.
My mom thinks I should just stay in this unit. I'd love your advice. Help!