Have you ever had someone on your mind 24/7?

Your answer can be anything. A lost love, an old gf/bf that did not work out, a deceased family member, a pet….anything goes. For some reason, I have had my mind on a person that I have never met. I do not know where she lives, I do not know that much about her. Her photo lingers in my mind day and night. I am wondering what is behind all these tormenting thoughts. Help! Question: anyone else been in this situation?