5 year old, fever around 104 only at night, slight cough, a little congestion, some pain in lower right side of abdomen, and now nose bleed?

Hard to say: This could just be a simple virus, or the sign of something more serious. You should take your child to the doctor very soon.

Sounds "viral": Your 5 year old if otherwise healthy & without chronic medical issues sounds like he has a "viral" illness/flu like illness that is causing all of your symptoms. Comfort care and support can be maintained and if he is worsening or not responding to your offerrings-have him evaluated by your pediatrician.