Did you apply for a nomination from the Vice President? You can do that easily and the deadline is probably approaching. Also, I believe you can be nominated by the academy superintendent if they decide they want you. I think the superintendent can nominate 50 per year. I also don't think you need a nomination to be selected for a Falcon Scholarship, or the Prep School. Can somebody confirm that part? Sorry, my answer is tailored to USAFA but it probably applies to USNA.
To be brutally honest, you have little chance of being appointed this year. If you want to try again next year, then you need to take a hard look at your file and determine what if anything can be improved.