Should Obsessive Behaviour Of Co-worker Be Ignored?

Is there a term for an obsession co-worker seems to have for me. She gets upset when I go eat lunch with the other girls in the office, she stares when someone asks me a question at my desk. my str stopped in and we went to lunch to discuss her wedding and gave her a hateful look. I have also learned that she is a cutter. She is somewhere in her 50 s and I am 60 The relationship has only been office related and no personal relationship Do I have reason to be concerned or do I ignore?