DD1 (3.6) was ill Thu and Fri with some kind of bug- temp hovering between 38 and 39, exhausted, sick once and coughing but no other real symptoms. Her temp has been normal sine Fri night but she's still utterly shattered and slept for several hours today. She normally bounces back very quickly after illness, so I'm slightly concerned. Is it normal to take so long to recover? When should I worry?