Suggest Treatment For Fever Along With Stomach Infection

my 19yr old son has been running a fever for about 3-4 days (varies between 99 & 102 degrees). It started with a stomach bug (which is better now) but he has seen a bit of blood in his mucus when he coughs and has what he describes as a back pain (spleen?) that has been persistant for the duration of this (what we thought to be) flu bug. He started taking Tylenol as well as DayQuil.....now he is taking Advil and TheraFlu. He first reported that he wasn t feeling well Wednesday and now it is Sunday. Any thoughts?