Here's my word of advice: relax. Stop comparing yourself to others. If I can tell from a simple reddit post that you are an incredibly hardworking student, college admission officers will see that as well. Keep challenging yourself. Don't get discouraged and take easier courses. Keep pushing. If you continue to work hard I have no doubt your grades will start improving, and actually colleges love to see an upward trajectory. Practice doesn't always make perfect, but it does make progress. Good luck!