I need reinforcement, how do you deal with the nasty emotionally abusive elder games, ploys of a moderate dementia parent?

My mother has become extremely petulant. If she does not get 100 percent of my attention, she tries everything from rummaging in closets to saying she is sick, she has been home the past two days from Adult Center because she said she was not feeling well, but she is fine, a bit of gas perhaps, but other than that she is incredibly nastier than usual. She is doing very strange things but it is put on, she pretends to sleep and when she thinks I am gone will peek out for me, she will run down the hall if she sees me. This is the wacko behavior that I worry about since she said to me the other day if I don't sit with her she will tell them at Adult Center I am not feeding her. I am so done with all of this, stick a fork in me.