Sorry you are under the weather. Had the same thing myself a couple of weeks ago. The best thing to do at this point since your shop is today is to
CALL the MSP scheduler directly, the sooner the better, and explain what's up. They can reschedule the shop for another day. If you don't get the scheduler for the shop, ask to speak to any scheduler. This way, the shop doesn't get cancelled and you don't lose points for not competing it. Hope that helps and feel better soon.
I had a restaurant scheduled for this past Sunday, needing to take a guest, which was planned to take my daughter, on Saturday about noon, my daughter had something to come up she had to take care of with her family, I was left to find someone else in a hurry, I reached out to 4 friends who could not go with me, I then sent an email to my msp person to let her know I may have to reschedule, I got a reply a few hours later asking for another date. but luckily in those few hours, I did find someone, so no need to reschedule after all, I was very happy with the entire situation, I did not want anything counted against me if I could not do the shop as scheduled but happy to know my msp was going to help me.