I have weird thoughts about my step brother

r/

I 17F have started having thoughts about my step brother, he is no biological relation to me but my mother is dating his father. He is a year younger than me, I’ve tried to get these thoughts out of my head but it has stared to eat me up inside and I think about it constantly, I’ve started having almost lucid dreams about it and it’s so embarrassing and weird. He was teaching me a video game the other day and was so nice and kind in a way that no boy has ever been to me. I’m genuinely horrified at myself and I don’t know what to do.

Please help, can provide more context if needed. Also using a burner account bcuz it’s so embarrassing. And no this isn’t some rage bait or something I genuinely don’t know what to do. I can’t talk to anyone about this