How supportive would your parents be about you seeking some help with those issues?
Could you phrase it something like this: “Mom, it’s really important to me to be successful in both high school and college. Lately, I’ve been getting overwhelmed. I’m so worried about getting the right grades and how to do all the other things I need to get into a good college that I just can’t seem to focus, get organized or even move on a plan. I just got my first bad grade in math and you know that’s not normal for me. Not only that, but I’m so worried that every little thing that happens, like this bad test grade, will cause my life to be ruined that the worry is causing even more stress and preventing me from doing what I need to do. Can we make an appointment with __________ to help me figure how how to 1) manage my time effectively and 2) manage stress?”
_____ will need to be filled in with whatever resources you have available locally that your family can afford. Could be a licensed child psychologist, a guidance counselor (who might refer you to someone else), a trusted clergy member who does counseling, etc.
But do get some help with this. If you can’t talk to your parents about it, let us know and we can come up with some other ideas.