I regret D studying so incredibly hard right up till she took the PSAT. In hindsight I wished I would have had her do NO studying and try to destress for 2 weeks preceding the PSAT. I am confidant test anxiety/nerves had a part in her unusual performance that day.
I like the idea of taking the next two weeks prep free. She very clearly has the foundation needed, test taking techniques needed , it has got to be the anxiety. Two weeks with no talk, and no prep could be just the ticket needed.