If you'd had flu, you wouldn't say that.
I had flu (and a consultant virologist confirmed it
was flu) just before Christmas. It came on suddenly (no coughs, no sneezing, no sore throat, no runny nose, etc .... in fact, none of the typical 'cold' symptoms). One afternoon I was feeling fine (if a bit hot, then cold), and that evening I felt a rough so went to bed early. By the following morning, I didn't know up from down. I had four days of hallucinations, drifting in and out of consciousness and I ended up in hospital with a temperature of 104.5. This is why a basic treatment for flu consists of paracetamol or aspirin (to keep temperature down), lots and LOTS of fluids (prevent dehydration) and plenty of rest. I lost about 10 lbs in that four days, probably due to sweating .... and eating
nothing.