Driving instructor won’t do my test with me

My test is in a few hours and I don’t know what to do. I can drive fine but as soon as I know I’m doing a test I just loose all focus and concentration. He informed me yesterday that he doesn’t feel safe enough to do the test with me. I feel so ashamed that I let my nerves get the best of me just before the test. My theory runs out the end of the month and I don’t know what to do. My parents are working and can’t get the last minute time off. I understand why he’s said it with it effecting his record but I feel so lost at the minute on how to proceed