I don’t know what to do😭

There is a girl at my school named Alexa (I’m in middle school) and i was never really very fond of her, but for the most part we didn’t really talk at all. Last night I was talking to one of my friends named Beth that is friends with Alexa. Alexa took Beth’s phone and sent me a text calling me a whore and told me to kill myself. I never slept with anyone before so idk how that makes sense but it still hurt. And she’s the one running to her boyfriend’s house getting hickies all the time. I have another “friend” named Lucas and he was in a group chat with the two of us and he was telling me to do it too. Then every 10 minutes or so Alexa would send me a text that says “Are you dead yet?” I have had suicidal thoughts and depression for a little while now and i am a very sensitive person so naturally I’m taking this very seriously. I also feel very weird about everything because me and my dad are really close and I tell him everything but this time I think he might overreact and I don’t know if I should. I’m nervous to go to school on Monday because Alexa sits next to me in one of my classes and I’m afraid she’s gonna have some smart comment to say and I won’t know how to react, because I’ve never been good with words and I always get tongue tied. Can I have some help please?😭