Having been someone who has failed checkrides and who has failed people on checkrides all I can constructively tell you is that is part of being a professional pilot. How you handle a fail is a telling test of your professionalism.
Don't try to find excuses, be chided but not gutted and crucially use the dissapointment to fuel the effort required to blow the examiners socks off next time.
Some of the best passes I have seen have been from people who have recently been failed or partialled...
Good luck,
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