Do you think your cat can sense when you have a fever? Because generally when I'm sick my cat sits next to me and doesn't give me any requests for food or to go outside.

Probably can see you behaving differently

Yes they notice changes in your behaviour,but not sure they know what sick is!

They could be attracted to the warmth your body gives off due to your temp. Or know you are sick. Mine are more cuddly too

There are two possible reasons as to why they do this... either they sit at the end of the bed plotting when they could kill me when I am at my weakest.

Or they are just defensive of their owners.

My cats curl up next to me when I'm sick. I can't explain why they do it, but it makes me feel better.