It could be. I am not the expert but I think that's a mix of people oddity. First of them is finding connections between unconnected situations (for example: yesterday I saw a black cat and today i broke my leg). Second is finding faces, words, etc. in regular things ("oh, that cloud is smiling" or "when you play that song backwards, you'll hear weird sentences"). And the last and the most important of them: she constantly thinks about him and his dead, and that's the short way to thinking about ghosts, etc. Her mind is full of that thoughts, and her imagination just boosting.