I agree that cats seem to know when you're not feeling well and want to offer some comfort. Our first cat Valentine (aka Bugby) wasn't much for getting in my lap at all (he preferred my husbands' company). The day I had four wisdom teeth removed, however, he jumped into my lap and purred and stayed there the entire day. On another occasion, my husband was in the bed with the flu and Bugby stayed with him the entire time, lying as close to him as possible and scarcely even going to the litter box.