At the beginning of the school year a new girls came to my school and I noticed that she don't talk to anyone much and she sat alone at lunch. so I decided to befriend her. After we became closer we started talking about more personal things. One day we we're talking and the topic of Crushes came up and she said that she had a crush. I asked her to show me a picture of him and it was MY BOYFRIEND! So I sarcastically said "yeah he's my crush too" and she picked up on my sarcasm and then I told her that he was my boyfriend. She didn't believe me. So she decided to go around and ask people if the guy and I were actually together and everyone told her yes. But she didn't stop there. she went to my boyfriend and asked him and of course he said yes. After she finally came to believe me she made it seem like I was the bad guy. She would " text me and say " you ruined my life! he was supposed to be with me" and " I'm going to tell everyone what you did to me". Like this girl is delusional. me with every time she sees him she always whispers something to her friends and it feels like she's out to get me. I don't really care about upset I just don't like whole having a high school enemy thing and I'm torn between telling her off or just letting it be. Any advice?