How do I forget this thought

So I’m totally straight but I can’t get this article I read in my English class about lesbians and it’s really confusing me? Like why is it always in the back of my mind. Also this Linda things always sit on my mind for a very long times, for example things that bother me. And it’s making me really depressed! I’m a 100% sure I’m not lesbian cause I like boys I’ve never liked a girl and also I have a boyfriend. But this thing it’s just bothering me