How would you read this?

I am a nanny and have inflammatory bowel disease. My 'Mum boss' texted me today and said my charge was sick in the night but fine now and was in a kid's holiday camp that I was meant to be picking him up from.
I said I was worried about looking after him if he had a bug because of my illness and that it would knock me for six. She then said she would leave work early to get him and said 'That's fine,I don't want you to be knocked for 6.'