Hi Hopeless

"I did not sleep well last night. Do you think that may affect my test today?"

This is a bit outside my expertise but I doubt it. Most circadian rhythms are linked to dark/night (low retinal stimulation) compared to light/day (high retinal stimulation) - probably your poor sleep will not be a major factor.

"I, too, think it was a lab mistake."

That would be my call - mistakes happen.

I hope that you get reassuring answers when the results come back.