Try not to worry! All my my ferals have reverted back to the litterbox sitting behavior anytime they are frightened as well! Usually in a day or so, they feel comfortable again, and go back to sleeping in more pleasant surroundings!! I think the fact that she is still coming out into the room is a very good sign, and I'm sure she will come back around completely in a few days. Mine always go back to questioning my loyalty to them as well anytime they are frightened. The good thing though, is each time, they take less time to decide I'm trustworthy again!!!