> Having a period does not require a visit to the doctor. Should I have brought in the bloody adult diapers as documentation?

I know, neither does being out cold with the flu for a week, but the person footing the bill is still reasonably entitled to some form of verification (regardless if this is the right approach in terms of good will or not) that you were unable to work (at least on location). Don't you agree?

I don't think your doctor would need verification for that note, diapers or otherwise. I assume it could be handled by phone.