“The Dean” can’t offer much help without knowing what classes you’re taking and what your curriculum covers.
But you may find that the Khan Academy will be useful. It’s free and provides lessons in countless subjects that are geared to students at varying grade levels. See https://www.khanacademy.org/
When my own son was about your age and was out of school for a week with the flu, he was able to keep up with his math class by using the Khan Academy lessons.
Another strategy you should try is to talk with all of your teachers individually. Explain that you want to do really well on your finals and ask the teacher to recommend pertinent Web sites or other study materials.
Not only are you likely to get some advice that is appropriate for each class, but also (and perhaps most important), you’ll be sending a message to your teachers that says, “I care about this class and want to do my best.”
So, when it’s time to grade your exam, the teacher may be more apt to give you the benefit of the doubt if there are some borderline areas where your grade could go either way because the teacher will know that you’ve made an extra effort to do well.