I'm assuming that you know these forums are not in anyway officially affiliated with any of the Service Academies. So I would encourage you to contact admissions.
However, I am puzzled as to why if you submitted your application in November that you did not take the SAT before the end of January. Typically, there are test dates in November, December, and January which would have worked for this year's applicants. January would be the last date you could take the test for summer of that year admission. This year some people were allowed to take it in February due to the January date being canceled in some regions.
I would think that the most likely outcome is that you would have to wait until next year and reapply. This would include your having to seek the nomination again. You can start your application before summer so you needn't wait too long to resubmit.
As to the prep school, that is never a guarantee. It's at the discretion of the USAFA. However, they may have more flexibility there in terms of how they treat your application.
In any event, you should really contact admissions to discuss your personal situation and figure out what your options are at this point.