Sheep may safely gaze

To celebrate my Covid test registering negative I go for long walk up the road and some sheep, newly arrived for their winter pastures, stand and stare curious that I am taking their photo.
 
My initial elation is somewhat spiked when I return home and  M tells me that the test now shows a thin red line. 
 
A friend who knows about these things says to ignore it. Hope she is right.