Well, here's one solution.
Take a PG (post graduate) year at any of the many boarding schools which have a 13th school year. This way you will have a year beyond your senior year to improve your grades and find an activity which you can use to distinguish yourself, especially a sport, which now you have the time for which to excel. If you do excel, there is a chance you can be recruited by a college. That is an excellent way to find yourself in the enviable position of being "the chooser" rather than waiting to be chosen.
Here's what you do. Inform your current high school over the summer that you are planning on taking a PG year, and that you don't feel ready for college yet. Ask for their help in recommending schools where they might have contacts or find schools on your own.
Set up a game plan for September of your senior year--contact 5-6 boarding schools, visit them, fill out and then send in your applications by January 1st, or whenever each boarding school's application is due. Acceptances generally come out in April.
If you have any questions, please contact me and I will help you.