What should I do if I'm still in love with my high school english teacher?
That sounds rough. What do you find appealing about her?
She has a decent job as a writer
It's not uncommon for people to get crushes on authority figures. It would only be an issue if she reciprocated your feelings while you were a student.
I'm still in love with her, but she doesn't pay any attention to me.
It's good to know that she's not interested in you. While it's normal for you to experience these feelings, it would be good to try to distract yourself from it. Keep the feelings to yourself and try to find someone your own age.