It sounds like you are feeling really unwell, and your health is the most important thing to consider. If you have a fever of 104.1°F, that indicates that your body is fighting an infection, and it's essential to take care of yourself. A fever of 100.9°F, even if it's below the threshold your school sets, still suggests that you are not in top shape.
You should speak to a parent or guardian about your situation—they can help explain it to the school and advocate for your health. Additionally, consider reaching out to a school nurse or counselor if available; they may have a better understanding of school policies and might be able to help you. Remember, your well-being should come first, so make sure to take care of yourself.