You Took Hard Classes and Got a Low GPA
Did you overload yourself with too many hard courses and struggle to keep up? In your essay, you could talk about what you learned from taking on too much at a time and how you will be more careful and focused in college.
Since you were in those hard classes, you should also highlight what you learned and any intellectual development you experienced. For example, even if you got a low grade in AP Biology, maybe taking it convinced you that you want to explore pre-med courses in college and so you began volunteering at a local hospital or signed up for a medical anatomy class.
That kind of journey would show colleges that you have serious interests, and even if your grades aren’t high, you are capable of doing hard work and improving.